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WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
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WATER CONTAMINANT LEVELS
WATER FILTERS, HOME USE
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL CHLORINATION & DISINFECTION
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
This article describes the causes of variation in building water pressure for homes connected to municipal or community water supply. These different causes for variation in water pressure help tell us what is needed to improve or regulate the pressure. The process of water pressure problem diagnosis and the costs of the repair are explained.
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Readers whose building is served by a private pump and well system should see WATER PUMP PRESSURE CONTROL.
Distinguishing between static water pressure, dynamic water pressure, and water flow rate can help diagnose water problems in a building. Here we explain these concepts and we describe how to measure water pressure and flow at a property where either municipal water supply or a private well and pump water supply is in use.
The water pressure regulator setting [public water supply] may not be the same as the water pressure you'll actually get in the building.
Depending on the size of the building, its piping size and length of piping runs, and the number of fixtures and number of occupants (and similar variables) in a building, it is possible to draw water out of the building supply piping at such a high rate that the overall building water pressure drops considerably below the pressure setting at the water pressure regulator.
The water pressure settings on your [private water supply] well pump pressure control switch may not be the same as the water pressure you'll actually get in the building. Similarly, the private well pressure control switch settings define the maximum and minimum water pressure you may see in the system, not the water pressure you'll see at any given moment when water is being run.
Even if every component of the private well, water pump, and water pressure tank and plumbing system are working normally, water pressure in such a building will fall between the time water is turned on and the time that the well pump is turned on by the pressure switch.
Key things to check when water pressure and flow are inadequate in a building served by municipal water supply are
Bad water pressure regulator or bad pressure regulator adjustment: (poor municipal water pressure) if the building is connected to a municipal water supply there may be a water pressure regulator installed, usually close to the water meter or where the water supply pipe enters the building.
Photos of water pressure regulators and diagnosis and adjustment advice are at WATER PRESSURE REDUCER / REGULATOR.
If the water pressure control was set too low to start with or if there is a problem with the water pressure regulator, you may see an improvement in water pressure by diagnosing and adjusting or repairing this control.
If the loss of water pressure was sudden, it's not likely to be a problem the pressure regulator except in the less common cases of a blockage or failure in the regulator itself. In this photo our flashlight lights up a (rather amateurish looking) water pressure regulator installed on a municipal water supply.
You can see that a previous connection to the water meter was cut, left shut off (see that shutoff valve at the left hand vertical pipe - what happens if someone opens that valve?), and new fittings were installed to conduct incoming water to the building water supply piping.
The use of smaller diameter flexible copper tubing might restrict the incoming water flow, but the presence of a pressure regulator at all suggests that the incoming pressure may have been excessive. (Too high water pressure leads to fixture leaks.)
Details about how to adjust the building water pressure regulator or pressure reducing valve are found at WATER PRESSURE REGULATOR ADJUSTMENT.
We have already mentioned checking and adjusting the pressure control for the water pump on a private well system - just above. But what if the home does not have it's own well - what if the building is connected to a municipal water supply?
Watch out: don't set the water pressure reducing valve higher than necessary. Doing so wastes water and as we discuss at WATER PRESSURE TOO HIGH: DANGERS, setting water pressure too high can cause both plumbing problems and actual serious safety hazards at buildings.
A Guide to Building Water Pressure by Adjusting or Repairing the Water Pump Pressure Control Switch on a Private Pump and Well Water Supply
For details about diagnosing poor well water pressure and flow, start at WELL WATER PRESSURE DIAGNOSIS or go directly to the individual items listed just below.
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Frequently Asked Questions (FAQs) about the causes and cure of unexpected or unwanted variation in building water pressure
Question: Water pressure varies while taking a shower; sometimes the warm shower gets too cold
I get a noticeable water flow variation, especially during a shower. When the well pump kicks in it over powers the hot water significantly making a warm shower cold. Any ideas what I should do?
Reply: Regulating water temperature at the shower during normal pump operating cycles
If your hot water runs too cool when the water pump turns I suspect that your hot water piping or hot water source is clogged - perhaps if you are using a tankless coil that is mineral clogged this would be more likely. You could install an automatic mixing valve right at the shower - that valve is designed to keep water temperature constant; first try partly closing the individual cold water shutoff valve for your bathroom - by this I mean a valve in the cold water line that is "ahead" of or before the shower itself. By restricting the cold water flow rate in the piping you may improve the pressure balance.
If you think your hot water piping is clogged see CLOGGED SUPPLY PIPES, HOT WATER.
It is normal for building water pressure to vary between 20-40 psi or 30-50 psi depending on how your pump pressure control switch is set. Even after you've de-clogged your hot water supply you can make a still better improvement in regulating water temperature at the shower by installing an anti-scald device or valve, either at the hot water source or right in the bathroom at the fixture.
See ANTI-SCALD VALVES for details.
Question: our water pressure comes on fast but quickly drops off to nothing. Is this a clogged pipe problem?
OMG my farm house was built before christ and my pressure gauge on my well has 60 psi works fine except I don't have any pressure in the house, I can turn on a faucet and it fast then drizzles down to nothing and if the kitchen sink is running there is next to none in bathroom, if filling washing machnine there is no water upstairs untill the washer fills up. takes at least 5-7 minutes for toilet to fill and 20 for the tub. How can I get the rust out of my pipes w/o tearing the house apart. I believe that they are clogged with rust since it is hard well water. - Lisa
Lisa if you have no actual water pressure but the gauge is reading showing pressure is present, and provided no one closed a water valve between tank and house, I suspect that the gauge pressure reading is wrong and the gauge is stuck. Try tapping on the pressure gauge to see if it moves.
Take a look at CLOGGED SUPPLY PIPING, but because the water pressure falls off quickly you'll also want to be sure that the water pressure tank is not waterlogged, causing the well pump to have to turn on and off too frequently. See WATER PUMP SHORT CYCLING to diagnose well pump short cycling and water pressure that rapidly rises and falls.
If on the other hand water pressure falls off and takes a long time to recover, I suspect that the well itself is running out of water. For that problem see WELL FLOW RATE and also how to measure the WELL FLOW RATE.
Thank you Mr. Friedman I will certainly try that with a light touch upon looking into the well I saw a capusule looking clear plastic part rustly what is that called and maybe that needs to be replaced I posted this alittle while ago and it didn't show up I turned all water off waited opened all faucets turn back on and no water b/c all faucets were open left only kitchen and water hardly any rust or air not like it use to when we hard power failure as no lights no water. Thank you for helping me, Lisa
Question: high water pressure, varying pressure, & burst components led to a leak
5/19/15 LB said:
All while back I had a problem with my water line bursting at my water meter. It happened on a day when the municipality had turned off the main water to all the rural area. When the water was turned back on, my line burst. I checked my water pressure at the meter and it is 102 PSI. Is that within a reasonable range? I also have a regulator in my home that was installed prior to me purchasing the property. From what I can gather, the previous owners had problems with seals and valves blowing, hence the regulator.
Indeed 102 psi is quite high and would be expected to give recurrent leaks at fixtures inside a building IF the building's water pressure regulator was not working or was not properly adjusted.
Watts corporation as well as other manufacturers produce a wide range of pressure reducing & regulating valves.
For high pressure commercial operations one might need to install a pilot-operated pressure regulator but in a private home that has very high incoming or widely varying water pressure it's more likely that a 2-stage pressure reduction that I will cite below is what's needed. Watts.com describes these products from which I paraphrase or adapt:
You certainly need a pressure reducing valve that can handle the pressure range your municipality delivers, which might mean installing two valves in series - a two-stage, "serial reduction" pressure reduction system. You don't
In sum, I suspect the problem is that the original pressure reducing valve you had installed was either improperly selected, adjusted, or perhaps it just failed.
Questions & answers or comments about troubleshooting the causes of varying building water pressure.
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