How to Diagnose & Repair Poor Water Pressure or Lost Water Pressure InspectAPedia® -
How to diagnose loss of water pressure or loss of water in a building - both municipal water supply and private well systems are addressed
How to decide if water pump pressure control switch or water pump replacement is needed
How to decide if water tank replacement is necessary
Typical cost of various well, pump, and water tank repairs.
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This article describes how and why to distinguish among intermittent water pressure loss, total water pressure loss, and poor water pressure or flow in a building. We give procedures for both municipal water supply problems and well water supply problems.
The process of diagnosis and the costs of the repair are explained. Consumer advice on saving money on water supply repair costs includes a review of the parts and labor costs of a typical well pump and pressure tank replacement case.
How do we diagnose poor water pressure or loss of water pressure in a building, and what are the common causes and repairs for this problem?
This sketch, courtesy of Carson Dunlop, shows five factors that affect the water pressure and flow in a building. What the sketch has not included are water pressure, quantity, or flow problems that originate at the well, well pump, or water pressure tank. Here is our comprehensive guide to diagnosing bad water pressure.
If you have no water pressure at all, see No Water Pressure and see the other water pressure diagnostic articles listed just below.
If your water pressure is intermittent, starts and stops, or varies in pressure, see Water Pressure Intermittent and see the other water pressure diagnostic articles listed just below.
If there is some water pressure but the pressure and/or flow are poor? See the diagnostic articles listed just below.
Keep in mind that if water is running elsewhere in the building (another shower, sink, dishwasher, clothes washer, garden hose, etc) then the water pressure you will observe at your location will usually be reduced.
If you have good cold water pressure but not enough hot water pressure or hot water quantity, see HOT WATER IMPROVEMENTS
If you have good water pressure at some fixtures but not at others, you probably have a clog in building piping (such as due to mineral deposits, rust, or even excessive solder in new work), or mineral and debris clogged strainers at faucets and shower heads (check these first). Also see Water pipe clog diagnosis and Water pipe clog repair guide.
How to Diagnose Poor Municipal Water Supply Pressure
Double check that there is no burst pipe or leaks in the building interior water piping
Check to see if there are leaks in the water supply pipe between the building and the water main in the street, and that there and no water running elsewhere before going on to more complicated water pressure diagnosis steps.
Listen for water supply main leaks: If your water is from a municipal supply and if you can turn off water right at the entry to your building, you can then listen to the piping - you may discover that there is an underground water main supply leak outside!
Check water supply main pressure and flow: Ask your plumber to measure the incoming water pressure and flow before the water pressure regulator,or with the pressure regulator set wide open. .
Water supply piping buried outdoors must be bedded in clean sand. Where copper water supply pipes have been buried in gravel, contractors find that over time the gravel, perhaps moving by frost or water passage through the soil, actually works against the metal water piping to create multiple holes and leaks in the water main.
One of our consultants, George from Jeneral Sewer Service reported that on excavating a water supply line with poor water pressure, he found that the entire length of the copper water pipe had multiple perforations - "When we dug it up and turned on water pressure at the curb box the water line looked like a sprinkler hose!" he said.
Where plastic water supply piping is used the risk of gravel perforation from the backfill material is little or none unless the excavator permits a large or sharp stone to become buried close to the pipe.
Poor incoming water pressure from a community or municipal water supply? How to boost water pressure in a building by installing a pressure booster pump and pressure tank for buildings whose incoming water pressure is too low or intermittent is discussed in detail at PUMP, WATER PRESSURE BOOSTER
Poor water pressure due to building height? How to boost water pressure in a building by installing a pressure booster pump and pressure tank for tall buildings is discussed in detail at PUMP, WATER PRESSURE BOOSTER
Poor water pressure just at certain plumbing fixtures? poor cold water pressure, hot water pressure, or both hot and cold water pressure or flow that is observed just at some plumbing fixtures in a building while flow and quantity are good at others suggests that the water flow or pressure problems are local to certain runs of supply piping or to the specific fixtures. Check the following first:
Clogged aerator or strainer on sink faucets - clogging by dirt, debris, corrosion, can significantly reduce both hot and cold water flow at a sink where the strainer needs cleaning or replacement. Unscrew the strainer from the faucet and turn on the water - if the fixture pressure or flow is much better you've probably found the problem.
Look at the aerator/strainer: inspect it, clean it, perhaps soaking it overnight in vinegar to remove corrosion and mineral build-up, or just install a new aerator/strainer.
Broken O-Rings on individual faucets - can clog the faucet internals and prevent good water flow. If just hot water or just cold water flow is weak at an individual fixture you or your plumber should check for and repair any damaged faucet parts.
Clogs in individual plumbing pipes, valves, elbows - can occur during construction if copper pipe soldering is not performed properly. Pushing too much solder into a copper pipe joint can result in weak flow and reduced pressure at all of the fixtures downstream from that fitting, even if the rest of the piping system is in good condition.
You may need help from a plumber to diagnose this problem, but if your water supply piping is not clogging from mineral deposits throughout, and if flow and pressure are bad just at some fixtures, this could be the problem.
Of course if an installer makes this soldering error on copper pipe joints near the beginning of a water supply piping system in a building, all of the fixtures downstream from that point will be affected, possibly all of the fixtures in the building. If mineral clogging might be a problem in the pipes in your building, see Water pipe clog diagnosis.
How to Diagnose Poor Well Water or Pump Water Pressure
The following articles pertain if you have a private well, pump, and tank system for your building or if your incoming community water supply pressure and flow are just too low to start with:
Water Tank Problems? See Water Pressure Tank Problems. Examples of water tank problems include poor water pressure or the well pump rapidly turning on and off (short cycling).
Water pump problems? Examples of water pump problems include poor water pressure or no water pressure at all. See
Water piping or well piping problems? If your water pump keeps losing prime, a shallow well jet pump well line could have a bad foot valve (in the well WELL PIPING FOOT VALVES) or there may be a bad check valve on well piping at or near the water tank or near the above-ground water pump (CHECK VALVES) and so be losing prime. A leak in the well line piping itself can also lead to loss of prime.
Well Problems? Do you run out of water or after running water for some interval water pressure and flow are poor? Well problem diagnosis starts at WELLS CISTERNS & SPRINGS. Before assuming that there is no water in the well, check to see if the water pump is working properly, including loss of pump prime (WATER PUMP PRIMING PROCEDURE) and a bad or leaky well piping foot valve (WELL PIPING FOOT VALVES).
Bad water pump or water tank pressure regulator control? See WATER PRESSURE REGULATOR ADJUST (not usually installed on private well and pump systems, often present on municipal water supply systems that use an in-building local water pump and pressure tank to boost pressure). Water pump pressure regulator switch diagnosis and repair steps include these:
How to Adjust Water Pump Pressure: The detailed, step by step procedure for inspecting and adjusting the water pressure control switch is
discussed in detail at ADJUST PUMP PRESSURE CONTROL.
Diagnosing Water Pump Short Cycling on and off: If your water pump is clicking on and off too often or quite rapidly see SHORT CYCLING.
Diagnosing Water Pressure Drops without explanation when the pump stops, see Water Pressure Falls Slowly, Erratic Pumping: bad pressure control switch, building water running or leak, bad pressure gauge, bad check valve, bad foot valve.
Diagnosing & Repairing Lost Air in the Water Tank: The problem of lost air in the water pressure tank along with how to correct that condition are discussed
beginning at SIGNS OF AIR LOSS.
Diagnosing & Repairing a Water Pressure Control or Water Pump Control Switch: We discuss diagnosing and repairing a water pressure control switch that sticks "on" or "off" or simply won't operate, at water pump Pressure Switch Repairs.
Bad Hot Water Pressure? See HOT WATER IMPROVEMENT especially if the building cold water pressure is acceptable but hot water pressure and flow are poor. Accumulated debris in a water heater, and debris from a corroded or disintegrating hot water tank dip tube or hot water tank sacrificial anode can also block the hot water outlet opening, resulting in low hot water pressure in a building.
Problems with water treatment equipment can cause loss of water pressure or no water flow: a clogged water filter, or a malfunction in water disinfection or other water treatment equipment can cause a reduction in water pressure or even a complete stop in water flow in a building. See WATER FILTERS for details about clogged filters, and see WATER TREATMENT EQUIPMENT CHOICES for our complete list of types of water treatment equipment.
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Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Thanks to Jeneral Sewer Service - George - 845-297-2285, a New York Hudson Valley drain and sewer cleaning and de-clogging expert for technical details and consulting on drain clog diagnosis and repair, including proper use of the Kinetic Water Ram for drain clearing - 3/14/2009
Thanks to our reader, Carole Cimitile, 2/17/2009, for reminding us that small problems like faucet o-rings, clogged faucet strainers and similar local plumbing fixture defects can have a big impact on hot water flow, cold water flow, or both hot and cold water flow and pressure problems.
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