Guest Essay by Kip Hansen
In the “make climate a part of every beat in the newsroom” mainstream media, we get stories like this in the NY Times tthis week: “To Save More Water, American Homes Need Smaller Pipes — Most of the plumbing pipes in the United States are oversize, wasting water in a time of increasing drought.” authored by Megy Karydes.
The piece is absolutely hilarious — the NY Times journalist somehow arrived at a very wrong interpretation of something that was explained to her:
“Oversize plumbing pipes move water inefficiently, wasting money and increasing the risk of waterborne diseases. And water efficiency is especially important as climate change makes droughts more frequent and severe.”
Ten points to the first few readers to spot the gross misunderstanding.
She goes on: “When the current method for sizing pipes to transport hot and cold water throughout the home was created in the 1940s, it was under the assumption that every fixture had to be able to support a line of people for the bathroom, like at a sports stadium at halftime, according to Christoph Lohr, a mechanical engineer specializing in plumbing systems and the vice president of technical services and research for the International Association of Plumbing and Mechanical Officials, a trade organization.” …. “But even during a party at home, there won’t be a line for the kitchen sink, the shower, the bathtub, the laundry machine, the dishwasher and the toilets, with people using them over and over. In other words, most plumbing fixtures in the United States are designed to accommodate total flow rates far higher than they will realistically encounter.”
Really? How did a matter of plumbing size get assigned to someone who must not even have a high school understanding about fluid flow or home plumbing system design?
Number One: Larger than necessary pipes do move water less efficiently – takes more energy to move the water through too-large pipes – and too large pipes, which don’t get a lot of throughput, can develop biofilms that can be the source of some illnesses.
[Update, 21 Nov 24, 1300 hrs, ET: There has been some correction/clarification on this point. An explanation of Christoph Lohr‘s point can be found at this page. Two issues: Over-sized pipes waste materials and add to building cost. Over-sized hot water pipes can lead to delayed hot water delivery to the faucet/shower (one has to run the water longer until hot water arrives at the sink) which lowers hot water energy-use efficiency and send fresh water down the drain unnecessarily.]
Number Two: Number One has nothing to do with the concept of “water efficiency” that is related to total water usage and thus peripherally related to drought.
In case Megy Karydes reads here, I will explain: The stadium example mentioned by Mr. Lohr has to do with the number of sinks, urinals, and toilets expected to be in use simultaneously, which requires a high volume water flow … the number of people waiting in line, does not affect flow of water at all (ever). In the journalist’s home, there may well be many people needing to use the sink or toilet but not at the same time…just one after another, which does not affect required water flow or affect choice of water supply line pipe size. Larger supply lines or larger pipes do not use more water (except to fill them initially) – water use as water volume depends on the outlet size and time the water is allowed to flow – in our modern US homes this is regulated by flow restricting washers, which are placed in the faucets and showerheads, with differing sized holes.
[Note: To clarify, flow is the amount of water moving through the pipe and out the faucet. Total water use is the volume of water used. Larger flows require larger pipes – just like fire hoses come in several sizes. But this does not apply to normal home water use. Water pressure also is part of the equation of water use – higher pressure through the same sized outlet increases water coming out of it .]
I bet you all already knew that, but it had to be said.
The size of pipes used in household plumbing does not affect water usage at all. [There might be a tiny itys-bitsy effect when the house water system is first filled, but that is all, a few extra gallons of water stored in the pipes, but this is not ongoing use.]
Household water use is determined by the length of time water is flowing and at what rate it flows through the system. Saving water is done installing:
1. Flow restricting faucets (either factory restricted or by the addition of flow restricting washers). Usually 2.2 gpm or 1.5 gpm (gallons per minute).
2. Flow restricting shower heads. EPA’s WaterSense standard is no more than 2.0 gpm.
3. Low-flush toilets. Current standard 1.6 gpf (gallons per flush) for solids and 1.1 gpf for liquids. EPA WaterSense high efficiency certified toilets use 1.28 gpf.
4. Water-saving appliances: washing machines and dishwashers.
5. Laws and regulations on landscape watering.
A bit of Home Plumbing 101:
A water service line comes from the water main to the house. The size of the water service line determines the maximum total water flow/volume (at normal water pressure) that will be available in the home. In my county, the minimum size of the water service line is ¾ inch. All new single-family homes here have ¾ inch supply lines while those with more than one living unit have 1 inch service lines because they will need more total water flow.
A water supply line means the pipe from the incoming water source to a water use point – like a bathroom. In the diagram above, the supply lines are blue for cold water and red for hot water. The hot water heating system has incoming cold water supply and outgoing hot water supply lines. There are T’s in supply lines that divide up the supply of water, sometimes through smaller pipes, and send it to the sinks, appliances, bathtub faucets, shower-heads and the toilets.
Personal Note: In my home, when I had a single upstairs bathroom remodeled into two smaller bathrooms – one with a tub and the other with a shower stall – I had to specify supply line size to my plumber. He wanted to use less expensive ½ inch copper pipe (this is before modern PEX piping). I specified ¾ inch supply for the hot water – as the supply line would feed two bathrooms for six people, three of which were teenagers, and a supper-sized hot water tank, as both showers were likely to be in use simultaneously every morning and evening.
Well, now, we have seen that home plumbing water pipe size does not contribute to “wasting water in a time of increasing drought.”
Wait! What does this have to do with droughts?
Nothing whatever. As in, nothing at all.
But are we “in a time of increasing drought”?
Not according to the IPCC. In AR6, Chapter 12, Table 12.12:
The IPCC’s latest estimate of the predicted time of emergence of various Climatic Impact-drivers (CIDs) – “‘Time of Emergence’ refers to the time when anthropogenic change signals emerge from the background noise of natural variability in a pre-defined reference period” — shows that no signal Hydrological Drought or Agricultural and Ecological Drought has yet emerged. Not only not happening in present time, but not expected to be seen by 2050 and not expected to emerge between 2050 and 2100. Despite what the mainstream seems to say every day, in simple language, increased and more frequent drought is just not happening.
There are a lot of doubts and confusion about drought. In the United States, the primary source of confusion about droughts comes from the NOAA’s National Integrated Drought Information System through its website at Drought.gov.
Information from drought.gov ends up in the main stream media as this:
In a Record, All but Two U.S. States Are in Drought
Which uses drought.gov’s illustration:
I am not contesting the image or the data behind it. But I will state categorically that it is the specific type of mis-information that we see all through the weather and climate news: The actual meaning of the image (in this case) received by the pubic will not be the reality – there is not any context or clear plain language statement of what the image means for the public.
Definition: “A ‘plain language statement’ in science is a concise summary of a … scientific finding written in easily understandable language, designed to be accessible to the general public without requiring specialized scientific knowledge.”
Why is it that the primary source of doubt and confusion about drought is the very agency department whose primary responsibility is to track and inform the public about drought conditions in the United States?
It isn’t that they are trying to fool the public with mis-information. They are not bad actors trying to push “The Climate Crisis”. They do good science and report their results accurately.
If so, why the doubt and confusion?
According to the National Geographic:
“Drought is a complicated phenomenon, and can be hard to define. One difficulty is that drought means different things in different regions. A drought is defined depending on the average amount of precipitation that an area is accustomed to receiving.” … “A drought in Atlanta could be a very wet period in Phoenix, Arizona!”
There are at least 11 types of droughts mentioned at aginfo.in (unfortunately no longer active, but the link goes to the ever-helpful Wayback Machine – I send money every time I am forced to use them).
Dr. Jim Angel, State Climatologist of Illinois, says this:
“Drought is a complex physical and social phenomenon of widespread significance, and despite all the problems droughts have caused, drought has been difficult to define. There is no universally accepted definition because: 1) drought, unlike flood, is not a distinct event, and 2) drought is often the result of many complex factors acting on and interacting within the environment.
Complicating the problem of drought is the fact that drought often has neither a distinct start nor end. It is usually recognizable only after a period of time and, because a drought may be interrupted by short spells of one or more wet months, its termination is difficult to recognize.”
So, when the NY Times prints (on paper or digitally) the image used above, they surely explain that this is a representation of an “index” called “U.S. Drought Monitor”. Don’t they?
Well, no, they don’t explain that that is what we are looking at.
The “U.S. Drought Monitor” is an index about drought: “A drought index combines multiple drought indicators (e.g., precipitation, temperature, soil moisture) to depict drought conditions. For some products, like the U.S. Drought Monitor, authors combine their analysis of drought indicators with input from local observers. Other drought indices, like the Standardized Precipitation Index (SPI), use an objective calculation to describe the severity, location, timing, and/or duration of drought.”
The U.S. Drought Monitor (index) is not an objective calculation about drought or it’s severity in any particular location….involving more than one measure plus “input from local observers”.
My home area is “in a drought condition” which had little or no effect for my family – other than we had to water the vegetable garden twice in a month – which is not different from non-drought conditions.
Here’s another look of the continental U.S. drought conditions produced the same week as the image above, for the month of October 2024, but using different indices:
While they are somewhat similar, they do not even duplicate the deep severe drought in southwest Texas and southern New Mexico. Comparing them side-by-side, or diagonally, often finds no similarity on a state or region basis. Two of the four indices show the Northeast US in fairly serious drought, while the other two show the Northeast to be wet (green and blues) which is the opposite of drought.
The US Drought Monitor drought index is a very subjective metric of drought – and mostly means “less rain over the period [week, month, year] than average”. What it does not mean is that local water companies have to start restricting water use or call for voluntary water usage.
However, lack of rainfall can and does affect some cities (megalopolises) that depend on rain-fed reservoirs for drinking water. New York city’s biggest reservoir is currently down to 60% of normal. It will fill back up when winter rains and snows arrive. In areas where large cities depend on water pumped from deep aquafers, long-lasting problems can develop as these deep aquafers take many years/decades to refill. This is not an effect of drought but rather an effect of over-withdrawal.
CONFUSED? I don’t blame you.
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Author’s Comment:
While researching for this essay, I came across this statement at the U.S. Environmental Protection Agency [EPA]:
“When you use these water–saving products in your home or business, you can expect exceptional performance, savings on your water bills, and assurance that you are saving water for future generations.”
My home water supply used to come from one of two wells on our property, not exceptionally deep, but we never ran the well dry. Now we have “city water” that comes from a small dammed stream five miles away, the dam creates a small pond. The water not used by the water treatment plant there runs over the dam and then down the hills eventually into the Hudson River, which runs to the sea.
This setup is the same as it is for NY City, though NY has many distant reservoirs. But in the end, the water not used by NY City flows over or through the dams, down rivers into the Atlantic Ocean. All the waste water from NY City also flows into the Atlantic (albeit with a great deal of loss from leaking aquaducts).
No amount of saving water from these reservoirs benefits “future generations”.
Fresh water, where it is in low supply, can be wasted, used in foolish ways like to water desert golf courses. But only when this ssavings is of water pumped from aquifers does this saved water benefit our children and grandchildren.
Do you know where your water comes from?
Thanks for reading.
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Below is NOAA’s Chart of US Precipitation since 1895. Besides
that, here’s what the IPCC says about future precipitation:
IPCC AR4 Chapter 10 page 750 pdf3
Mean Precipitation
For a future warmer climate….. Globally averaged mean water
vapour, evaporation and precipitation are projected to increase.
Now tell me about drought
Manbearpig says it can be dry and wet at the same time. Boiling oceans can do that.
Steve ==> It is all definitional — and depends on the exact period and index being discussed. That’s why it is confusing.
The drought the press is pumping out scare stories about would appear on that chart as the down-pointing peaks. But ALL drought also depends on the specific geographical areas …. and CONUS is not an appropriate area to consider when speaking of drought.
Very nice Kip, I think most people in the US would think they were in perpetual drought if they received the average annual precipitation that my town receives. Fourteen inches.
Same here, but a lot of that 14 inches is the liquid equivalent coming as snowfall.
Bob ==> The most basic definition of “drought” is less rain than usual….a little less is the yellow areas on most drought maps, and can be for periods as short as a week, or month.
Yes and NJ has certainly been in a drought, today was the first significant rain since August. No rain at all in September and October, certainly not normal. We have had water use restrictions for some time.
Phil ==> Yes, that is one of the major points. NJ/Metro NY is experiencing a precipitation drought. All that summer moisture caused grasses and weeds to grow with abandon, and then they dried to tinder in Sept/Oct — now careless and malicious people are setting fire to those dried weeds.
Phil ==> In your case, water use restrictions are a result of increased population (and industry) combined with a failure to increase the number and sizes of reservoirs.
As well as no rain for three months where the monthly average is ~4″.
The grass in my lawn certainly didn’t “grow with abandon”, I only had to mow my lawn twice during the whole summer!
There’s a spot under my house that Never gets.rained on, I guess it’s in a state of extreme perpetual drought
The volume of water used in a household is dependent on the diameter of the outlet fitting (faucet, showerhead, etc.) and the pressure behind it … and of course, how long you stand under the shower. All good.
However, this is not correct, “Fresh water, where it is in low supply, can be wasted, used in foolish ways like to water desert golf courses.”
Most (all?) desert golf courses use treated effluent to irrigate, you can check this with the USGA.
Streetcred ==> Maybe….didn’t mean to step on anyone’s golfing toes. I could have said “watering home lawns and street medians”. Using treated effluent is a good idea, where the infrastructure exists to make it possible.
In Salt Lake City, every home has a nice green lawn, planted as sod, laid over raw sand….
Sorry not true, I live in Arizona and the golf course in my development get their water from wells.
The ignorance around water capture, storage, treatment and distribution is quite alarming. Add to that the concept of water being wasted as though it goes away somewhere is also a worry, it is the ultimate renewable resource. Articles like this add greatly to the necessary general knowledge and hopefully helps to point out the lack of knowledge in the media folk of anything useful. Another cool contribution by Kip Hansen.
Keitho ==> Thank you, sir.
Yup – just like carbon, water is neither created not destroyed. It is processed and perpetually recycled.
These people try to come up with new and original ideas to fuck with the populace.
It is impossible to “waste” water. The amount of water on earth is not decreasing. The only thing that can be done is to exceed its supply, which is a management problem. ALL water goes back to the oceans eventually.
// ALL water goes back to the oceans eventually.
What about water bonded molecularly to rocks and minerals? Clathrates etc? I suspect most of those hydrates will be bound forever until the Earth crashes into the Sun.
The process of binding and releasing water is likely balanced by now. The exception would be the released water through the burning of fossil fuels. insignificant? Probably.
Oh yeah, well explain the existence of ‘wastewater plants’. Do a search, millions of hits. That’s right, there are plants out there that actually waste water…..gotcha!
LOL!
Wow, you must be a Great Dad!!!
That was a Great Dad Joke.
I predict a drought at the Guardian
Journalists at the Guardian and Observer have voted to strike for 48 hours over the planned sale of the Observer newspaper
Newspaper articles begin a slight slant to the right for the next 48 hours
I promise to do my part to preserve fresh water supplies by burning as many fossil fuels as I possibly can, thereby producing extra CO2 so that all plants can survive with less water!
In my neck of the woods, many people have installed rain barrels to collect summer monsoon rain for watering their gardens. I use mine for my solar powered, Red Neck Mountain Hummingbird Water Park! I enjoy watching the birds making use of the facilities for their daily ablutions, especially when a hummer starts dancing in the fountain spray. Strangely, none of them seemed confused about their gender OR species!
I notice that right now, ironically most of Southern California isn’t in a drought. The rest of the country is a little dry, and in autumn during La Niña as we transition from the wet summer to periods of more frequent winter storms, it’s often a bit quiet. It will change, trust me.
Johnesm ==> The type of drought that is actually serious for most areas is long-term extreme drought. These happen occasionally and have damaging effects these environments. In ancient times, the terms for drought and famine were the same — extreme long-term drought meant failed crops which meant famine. The Bible (and Josephus) records more than one of these the Near East.
Kip, I draw your attention to The Lancet’s recent claim that that the area of Earth in extreme drought has tripled since the 1980s, as reported by the BBC. I looked into the basis of its claims at Cliscep. There were quite a few layers of the onion to peel away, but as you and WUWT readers might already have worked out, the claims were not true.
Jit ==> The Lancet is no longer a reliable source of medical information. It has become an advocacy group for various movements — including the Climate Crisis movement.
It actually IS this simple: COLD causes drought; warming causes precipitation.
I once won an email “debate” with a CAGW believer PhD hydrologist on this point. Checkmate was when I brought up the tropics – where it rains the most AND most of the sun’s energy arrives. To his credit, he didn’t try to say “but temps are lower” because he surely knew that the heat is locked up in humidity, what us engineers call enthalpy and internal energy – it’s there, just thermometers don’t measure it.
Geologists are well aware of this; so says my brother, who taught college geology.
One of the sinister, or ignorant, things Big Media and politicians do, evidently to stoke a scare in an ignorant populace, is to conflate heat with drought – to the ignorant, it makes sense: Deserts are often both hot and dry. But what even school kids USED to be taught is that between a desert and the ocean was always something like a high mountain range, that “wrings” the moisture from the air as it’s forced up. Who knew? I guess not Ms. Karydes.
Rod ==> Ms. Karydes seems to know only what she is told to write — very common among young journalists. She is told: “Write about this building codes guy saying water pipes in homes are too large and are inefficient — Tie it to wasting water in times of drought.”
So, apparently, or possibly, she does. Her High School education should have included in her general science class the facts she would need to know that the very idea was wrong.
When there’s a pay check involved…..
Very likely! They are SO ignorant (or dishonest, or both). I spent 30+ years as a professional electrical engineer, mostly in FL, AZ, CA. I was expert in the electrical code, but not the plumbing codes. Still, there’s a lot of crossover, so I know quite a lot about them.
Do the 1.6 GPF toilets save water? Probably. But there is a price seldom discussed: Not only do they not flush as well, but to use such little water. they flush violently. Sometimes even ejecting water (and *%#) to the floor. Not very sanitary! I own a small motel in Alaska. I disabled most of their restrictors. I have my own well & waste systems, and I do not need that BS.
A pity that the IPCC doesn’t have an active press correction office which could write a correction for every MSM piece which contradicts the IPCC position.
Although I suspect the papers’ editors wouldn’t print the corrections anyway.
Sea Dog ==> The papers wouldn’t print it — because then they would be shown to have printed official Climate Change Misinformation which is defined as information that contradicts IPCC viewpoints.
Duplicate posting deleted. Dunno what happened.
Sea Dog ==> I seldom do either….
Actually, as a matter of engineering, larger pipes move water more efficiently than smaller pipes.
The continuity equation for pipe flow holds that water flow velocity is a function of water volumetric flow (as in gallons per minute) and pipe cross-sectional area. The higher the velocity, as in a smaller pipe, creates higher frictional losses, which means it takes more energy (supplied either by gravity or a pump) to move the same volume of water.
Whether biofilms form on pipe walls or not is not really a significant issue. Typical municipal water systems in the US and most advanced nations are treated with chlorine as a disinfectant, which also hinders any biofilm development. Even if a biofilm forms its surface is going to be smoother than the other reasons that cause pipe friction (and thus friction losses) to increase, making water transmission less efficient.
The biggest reasons for increases in friction between water flow and pipe walls are 1) corrosion and 2) mineral deposition (i.e., hard water). Both processes create relatively high friction losses, and in the case of mineral deposition, over time it can actually completely clog up the pipe causing a massive reduction in flow capacity, or even a complete stoppage.
The only way that larger pipes can be less efficient is strictly in the construction/installation cost of the water supply and distribution system where of course larger and more costly components drive the installation cost. But that is a one time only cost that is far exceeded by the operational costs of any system over its projected lifetime.
Besides, water demands can change a lot over time depending upon number of occupants and how water is used in the household.
The reality is that engineers have to deal with wide ranges in flows and pressures in any real world system, so it is not as if pipe sizes can be completely optimized by the expected demand based flow of any fixture.
Generally, engineers shoot for water pipe designs that result in around 5-6 ft per second maximum or nominal flow velocity not to exceed 10 fps where friction losses really begin to mount up.
Duane ==> Thanks for the more complete explanation — I’ll have to look more closely at the referenced complaint of the Building Codes guy.
Duane, your explanation looks physically sound. I’m an EE, but as I recall, mechanical engineers say water flow calcs are analogous to ohm’s law for a wire. Which tells us that the power (= energy liberated/time) used by a current in a wire is (simple case) i^2(R). So if R decreases (i.e. larger wire) the power clearly decreases. Well, a bigger pipe all things being equal, has lower resistance. Hence, less power to flow the same amount of water.
Sorry, but you have basic hydraulics wrong when you state “Number One: Larger than necessary pipes do move water less efficiently – takes more energy to move the water through too-large pipes”
Flow resistance in fluid pipes is related to their diameter in a dramatic manner. It’s either a squared or to the 4th power relationship. Smaller pipes of the same wall smoothness will have considerably more flow resistance than larger pipes. Hence will require higher power to move water through them at acceptable pressure and flow rates.
https://calculator.academy/flow-resistance-calculator/
0.001 Pa.s viscosity
65 feet pipe length
0.5 inch diameter
0.1 liter/min flow rate
194 Pa/m flow resistance
And if you increase to 0.75 inch diameter pipe the flow resistance drops to 38 Pa/m. That is 5 times more flow resistance for one half inch pipe vs three quarter inch pipe, given the same length and flow rate of water.
So no smaller diameter pipes will require more energy to move the same volume of water, hence are less efficient in terms of energy to move that water. And no smaller orifice outlets are not “acceptable” for faucets, showers or toilets!
A simple example augmenting your post.
A garden hose. Turn the water on and it flows out with about a 6 inch arch.
Now cover the end with a thumb. Restricting the diameter results in a spray that goes out several feet. Same water volume. Same water pressure. Higher flow rate.
Sparta => Hmmmm….the flow rate is the same, maybe even lessened, when you place your thumb over the end. But the orifice is restricted and thus “partially covering the hose’s opening increases the exit velocity of the water, resulting in a greater squirting range.”
Actually, no.
When water is flowing freely out the unrestricted end of a garden hose, the water pressure just upstream of the exit is only slightly above atmospheric pressure, for example only 0.014 psid higher for a 0.75″ ID garden hose flowing 2 gpm.
When one places a thumb over the end of that garden hose, that restriction increases the water pressure just upstream of that partially blocked end and reduces the overall flow rate.
Bernoulli’s law states that for a given fluid flowing through an orifice the change in stream velocity will be proportional to the square root of the change in pressure drop across that orifice. So to make a hose stream go four times further (~ four times faster) than it does with an open end, one needs to increase the flow pressure by a factor of 4^2 = 16. (This assumes the discharge coefficient of partially-thumb-covered exit remains around 1.0 . . . reasonable since it won’t be anything like “sharp edged”.)
In the above example of 2 gpm from an open end 3/4″ garden hose, this would require one’s thumb holding back an increased pressure just upstream of the exit of only 16*.014 = .22 psid, quite doable.
The water pressure at the exit of the garden hose DOES NOT remain constant when one restricts its flow with a thumb.
You’re confusing velocity and flow rate. For the same static pressure supply, lower area means higher velocity/lower flow rate, and vice versa.
Actually what you describe is how the continuity equation works in pipe systems. At a given supply pressure and volumetric flow rate, reducing the cross sectional area by crimping down the outlet causes flow velocity to increase. Higher velocities result in higher momentum of the discharge stream which causes it to flow a longer distance at a flatter trajectory.
Except for the fact that volumetric flow rate is NOT constant when the cross-sectional area of flow is reduced . . . so the continuity equation is not applicable in this case.
The simplest way to see this is to consider what happens when a valve closes off the flow of water in a pipe (an analogy to one’s thumb gradually closing off the flow area at the outlet of a garden hose).
With the valve fully open, max flowrate out of the valve is achieved, but as the valve is gradually closed, the flow rate gradually decreases . . . down to just a trickle right before the valve is fully closed. The volumetric flow rate through the pipe and its outlet from the valve decreases the more the valve is closed. Therefore, the continuity equation is not applicable under conditions of ever increasing flow restriction (i.e., ever increasing reduction in flow area).
Actually, you are wrong – the inlet flow rate has to equal the outlet flow rate by the continuity equation …. you are confusing two different processes. The result of constricting the cross-sectional area changes pressure energy to velocity energy at the outlet and will not necessarily change the volumetric flow rate, but it can.
The continuity equation always holds – it is impossible otherwise as a matter of physics.
It is true that throttle valves are designed to make gradual reductions in volumetric flow rate. But most throttle valves make little difference in flow rate until they are shut quite a ways.
If you ever heard of a venturi, that is a constriction in a pipe that is used to measure flow rates. A pressure sensor in the middle of the venturi throat reflects the increased velocity in the venturi as compared to the output from another pressure sensor upstream of the venturi, but as soon as the flow is past the venturi and the restriction is no longer present, the velocity goes back down again while the volumetric flow rate remains the same. It is just a conversion from pressure energy to velocity energy then back again to pressure energy. There is a very slight reduction in energy referred to as a minor loss, but the flow rate is still controlled by the continuity equation.
A venturi in a pipe is a fixed, NOT varying-with-time, geometry.
The continuity equation is based on flow geometry that does not vary over time (but can vary over flow distance, such as in a pipe constriction) and that has fixed flow rate: volumetric flowrate = v1*A1 = v2*A2 = constant.
Fluid dynamics 101.
Sparta, incorrect. Try this: Take your hose, a bucket, and a stopwatch. First check the time to fill it, unrestricted. Then restrict it with your thumb. You WILL measure a longer period to fill it, for reasons others have discussed.
If this was not true, most of modern Newtonian physics would be incorrect, and “nothing” would work.
Don’t feel bad. This is what science is all about. We all go through it.
In fact, the pressure loss per linear foot length in pipe flow can vary considerably, and not just based linearly on pipe inner diameter and linearly on inner wall surface roughness, but also based on the fluid flow Reynold’s number and the number of bends and contractions/expansions along the pipe route. (See attached engineering graph).
So in fact, if the pipe is large—but not too large—for a given average flow rate yielding Reynold’s numbers in the range of 1,500–2,200, that laminar flow will have lower friction factors than those associated with smaller diameter pipes having a turbulent flow Reynold’s number above 4,000 for the same flow rate and wall surface roughness of 1% or higher.
If “moving water inefficiently” is meant to refer to the loss in pressure from source to user, one cannot definitely say bigger pipes are necessarily more inefficient that smaller pipes. However, it is certainly true that smaller diameter pipe are less costly than larger diameter pipe for the same design maximum operating pressure (MOP) and length of run.
BTW, it is ridiculous to assert—once a given water distribution piping run is filled with water—that using bigger pipes is “more wasteful of water” than using smaller pipes. Assuming no piping leaks, any “waste of water” is determined by the end user, not the volume of water contained in the water distribution system.
Finally, I’ll contribute my earned points to charity. 🙂
Ooops . . . here’s the engineering graph I forget to attach to my above post
(courtesy of https://www.pipeflow.com/pipe-pressure-drop-calculations/pipe-friction-factors ):
ToldYa ==> Your points have been donated to the Nature Conservation Fund — to save water for future generations.
Excellent! . . . thank you.
Ironically elbows, T’s, Y’s etc get classified as ‘minor’ losses, but make up the majority of pressure losses in most plumbing systems. I always shook my head when I was designing manifold and distribution systems because of that. One of the methods for characterizing piping system losses is to convert a fitting into “equivalent feet” of the same diameter pipe. I understand that came about because in large scale regional water distributions and irrigation type environments there are relatively few elbows and such but can be miles of pipe. Once you start to add fittings, though the basic pipe drops out of importance very quickly. I would frequently have to upsize piping simply because of the number of elbows, and branches required to get the water where it needed to be. I might only need to move the water 10 ft, but if it needs to go through 6 elbows to get around building corners, I would frequently have to go up 50% on a diameter.
D Boss ==> Did I accept the statement of the building codes guy to easily — certainly the use of too much unnecessary physical material is inefficient — copper (not used that much anymore in new construction) and plastic in the pipes.
So — yes — possibly mea culpa!
Places with reasonable regulations do desalination at reasonable cost with little or no environmental impact.
Most global population lives near coasts.
Ag water from reservoirs can be a real issue. Most other water discussion is just ignorant political blather.
Actually de-salination with transport to reservoirs is a great application for solar/wind. It is not time critical or rate dependent as such. Reservoirs perform the roles of battery’s/storage to buffer the general populace from variabilities. If the reservoirs have some level of hydroelectric you can even get some of the pumping costs back.
idiocy.
I remember ask a kid in our house how when someone else turned on a spigot somewhere else, mine would slow down. That’s when I knew the planet was doomed.
JBP ==> Or getting scalded or cold shocked in the shower.
We had a long dry spell here in Oklahoma. It had not rained in about two months and all the grass was starting to turn brown. But in the last two weeks it started raining and I got about seven inches of rain here at my house. The grass is greening back up. 🙂
Droughts come and then they go. Some last longer than others.
National weather forecasters last week were noting a “record drought” in the Northeast but now the rain and snow are moving in and the drought is over.
There is no evidence showing that CO2 has anything to do with how regional weather unfolds. None.
“Here come de heap big warmy. Bigtime warmy warmy. Is big big hot. Plenty big warm burny hot. Hot! Hot hot! But now not hot. Not hot now. De hot come go, come go. Now Is Coldy Coldy. Is ice. Hot den cold. Frreeeezy ice til hot again. Den de rain. It faaaalllll. Make pasty.”
Tom ==> Here in the northeast we had a relative wet summer and then a dry fall. The result was a lot of tall grasses and weeds that then dried into tinder. Arsonists are having a ball setting small “wildfires” (really grass and brush fires) while other human activities (leaf burning, careless cigarette butts tossed out of cars) start other fires along roads and highways. I am going to write about this phenomenon.
I once tried to explain to my adult daughter–she was a fine arts major with little science background–what happens to the water she does not use because she was “saving water”–that is, that it goes down the river into the sea. In reality the only thing she was saving was some money (good!) and maybe some electricity and treatment costs incurred at the water treatment plant. But not water.
That said, I live in Kansas, and in western Kansas, as well as most of the high plains. water comes from the Ogallah Aquifer, which is being heavily drawn down by all the water pumped out for irrigation. There really is a water supply problem there, and it is not uncommon for people to have to drill new, deeper wells, because the old shallow one has gone dry. But that is not a drought problem either.
starzmom ==> The overuse of the aquifers is a BIG issue and needs to be resolved before there is an even bigger negative effect. They should not be irrigating crops there — Dryland farming is indicated for that area.
Shallow wells are not really the right thing either … too easily contaminated. My wife and I ran a humanitarian program coordinated with the national water department in the Dominican Republic to drill deep, safe drinking water wells in the Dominican countryside — a lot of details but deeper is better.
When I bought my home we had a fairly shallow water well which could get a little iffy in a droughty summer. Fortunately, at the back of the property, where they used to fire clay roofing tiles, there was a deeper and more modern commercial well that we could use as backup. (We pipped it to the neighbor’s house one summer when his well failed altogether.)
My son’s house still has, “out back”, a hand-dug pit well….not in ue now of course, but we had to cover it to keep the dog from falling in.
One of the biggest problems with the overuse of water in western Kansas is that water rights are real property rights, which cannot be unilaterally terminated as that would be a “taking” under the Constitution. Unfortunately, water has been over-committed under the state water rights programs. Use can be temporarily curtailed for junior rights holders, so as to provide for the senior rights holders. Some people, regardless of how senior their rights may be, simply can’t pump their allotted quantity because the water isn’t there. I no longer follow it the way I did a few years ago, but I understand the situation is worse, not better.
Lots of people are trying to come up with better genetically engineered crops so that dryland farming would yield the same harvests as irrigated crops. One idea is to engineer wheat to grow as a perennial crop rather than an annual, with the same yields as the annual wheat strains. The guy in charge of that research project was very optimistic, but last I heard had not had the breakthrough in his research that was “just around the corner”.
And of course, one can readily figure out where the flow restrictor is on a shower head. But no good little weenie will ever remove or ream it, I promise!
Tom ==> If the wrong people ask, I didn’t remove the Flow Restrictor Washer from mine either. Honest (but fingers crossed….)
Resource management, aka conservation, versus ideology.
I go with management.
Letting the faucet run needlessly is wasting POTABLE water. That puts added burdens on the upstream system, purification plants, and the like. But the water itself is not wasted. It is reentered into the natural hydrologic cycle.
Nature conserves water.
Sparta ==> Yes, people can let far too much water run down the drain needlessly. Teenagers in the shower?
Sparta ==> When young and foolish I was a Merchant Mariner — working on ships. Fresh water, in those days, had to be purchased when in port and stored in the shipboard fresh water tanks. Sometimes the local water was too expensive (at least for the owner of our ship) and he would restrict fresh water use so it would last until we reached a more economical port.
We always require to take “ship showers” — two minutes max running the water. Longer and one risked being reported to the ship’s water use police….a bad thing.
A simple google of the author Megy Karydes put a bit of color on this piece.
She has a recent book 50 Ways to More Calm Less Stress. Well that
explains it all. Drought as I’ve experienced it as a Ag Producer is very stressfull.
I have access to irrigation water via a ditch company but up in the mountains
on other property the stress level this past year has been high. Miles of dead trees
with no rain or snowpack last year. The springs and small creeks dried up which
really stresses out the wildlife and livestock. Producers without irrigation are
in a serious stressful situation Ms Karydes can’t even imagine. The Pineapple Express
on the coast is encouraging .
Mr. Ed ==> What state are you in? Southern Oregon? I have explored the interesting water ditch system in and around Ashland, OR.
Serious, long-term drought is bad. Week-length local drought is often not even inconvenient.
The US Drought Monitor does not properly tell the general population the differences and implications.
I’m in West Central MT along the continental divide. I’m fortunate to have
access to Missouri River water on a old Pick-Sloan project from the 50’s,
I also have some water rights from some creeks
but they went dry early this year. My pumps electric bill has gotten very high
over the past 10yrs or so. I pay more for a weeks use than I used to pay
for an entire season. Most years I can buy hay cheaper than I can grow it but it’s
these dry years that will make/break you. My neighbor went big a few years ago and
hit a dry year with a large crop of hay to sell. Not sure what he made but he
bought a new JD tractor/loader and a new smart MoCo, easy $600K++ that spring.
That raises the question”
How frequently does it rain where you are?
A month here without rain has us thinking half an inch in the next couple of weeks would be handy, but it’s hardly a drought.
Drought is simply a trend in precipitation amounts that continues for varying lengths of time. In my area it has been so long that every conversation about snow or rain is appended by the observation “but we need the moisture.”
Many water bodies are dry basins by fall and provide visual confirmation of a drought situation that can vary by just a few miles in an area where even a thunderstorm can be significant. All this, however, is normal variation in the shadow of the Rockies and usually not a reason for hand wringing..
My house water comes from an underground flow that starts miles north of me and 4,000 feet higher. My pump is 65 feet down. At the house, precipitation is <10 inches / year. Underground is busted basalt cobbles and all that came with it over the last 10 M years.
“When the current method for sizing pipes to transport hot and cold water throughout the home was created in the 1940s, it was under the assumption that every fixture had to be able to support a line of people for the bathroom, like at a sports stadium at halftime”
WRONG.
Water usage is calculated using fixture units. A sink or toilet has a different multiplier depending on whether it is single family, office use, restaurant use, or assembly use (stadium at halftime) they are not at all designed the same.
Ann ==> Yes, you also get the Ten Happy Points! Nice job.