Low Water Pressure in House? How to Find the Cause
Short answerLow water pressure at one faucet usually means a clogged aerator or a partly closed valve under the sink. If the whole house is low, check that the main shutoff is fully open, then suspect a failed pressure regulator, a hidden leak or old pipes. Ask your water utility if neighbors have the same problem.
Safety first
- Before you unscrew anything at a fixture, close the valves under the sink.
- If you find a wet wall, ceiling or floor, shut off the main water valve and call a plumber. Do not touch outlets or switches near standing water.
Likely causes
| Cause | How to tell | What fixes it |
|---|---|---|
| Clogged aerator or showerhead | Only one faucet or shower is weak. | Unscrew it, clean it and soak it in vinegar and water. |
| Valve partly closed | One fixture is low because of the valve under the sink, or the whole house is low after recent plumbing work. | Open the valve under the sink or the main shutoff all the way. |
| Failed pressure regulator | The whole house is low, both hot and cold. East Valley Water District in California says the regulator is often near the front hose connection; yours may be elsewhere. | Have a plumber test and replace it. |
| Peak demand or a utility issue | Pressure drops mostly in the morning and in the afternoon or evening, or neighbors have it too. | Call your water utility. |
| Hidden leak | The water meter moves when nothing in the house is using water. | Call a plumber to find the leak. |
What you need
- Adjustable pliers
- Rag
- White vinegar
- Small bowl
- Screw-on water pressure gauge (optional)
How to fix it
- See how far the problem goes. Test the cold and hot water at several faucets and outside. One fixture points to that fixture. The whole house points to the main valve, the regulator, a leak or the utility. If only hot water is low, the problem may be at the water heater, so call a plumber.
- Clean the aerator. Close the valves under the sink, unscrew the aerator at the tip of the faucet and rinse out the debris. Soak it in a 50/50 mix of warm water and white vinegar if you see mineral scale. Screw it back on.
- Open the valves fully. Check the valves under the sink, then the main shutoff, usually where the water line enters the house. In some areas, such as East Valley Water District in California, it is near the front hose connection. Open them all the way, especially if someone recently did plumbing work.
- Check for a leak. Read the water meter, use no water for two hours, then read it again. If the number changed, you likely have a leak.
- Test the pressure. Screw a gauge onto an outside hose connection with everything off. One water heater maker lists 50 to 60 PSI as the target and never above 80 PSI. Share the reading with your utility or plumber.
When to call a professional
- The regulator needs adjustment or replacement.
- The meter shows a leak you cannot find.
- Pressure is low throughout the house and your neighbors are fine.
Common questions
Why is my water pressure low in just one faucet?
The usual reasons are a clogged aerator or a partly closed valve under the sink. Both are on your side of the meter and are simple to check.
Why is my water pressure low all of a sudden in the whole house?
First check whether the main shutoff was left partly closed after recent work. Then ask your utility about nearby work. If they find no problem, a failed regulator or a leak is likely.
What should my home water pressure be?
One water heater maker lists 50 to 60 PSI as the target and says it should never be above 80 PSI. Your utility can tell you what to expect on your street.
Can low water pressure stop my dishwasher or washer from working?
Possibly. GE lists recommended ranges of 20 to 120 PSI for dishwashers, 20 to 150 PSI for top-load washers and 10 to 120 PSI for front-load washers. If yours is below the range, check your own model's manual, since limits vary. Source
Why does low water pressure cause a boil water advisory?
Positive pressure in the pipes helps keep outside material from getting in. The City of Elkins, West Virginia, for example, explains that when pressure drops across enough of the system, that protection is lost and contamination could occur. Follow your water utility's notice until it is lifted. Source
Related repairs
- Burst Pipe in House? What to Do First
- Clogged Drain? How to Unclog a Sink or Tub
- Frozen Pipes? How to Thaw Them Safely
- Garbage Disposal Not Working? Reset and Unjam It
- Leaky Faucet? How to Fix a Dripping Faucet
- No Hot Water in House? What to Check First
- Sewer Smell in House? Causes and What to Do
- Toilet Keeps Running? How to Stop It Yourself
Last verified 2026-11-01
Sources
- East Valley Water District: Water Pressure Help — Causes by location (aerator, under-sink valve, main shutoff, failed regulator), regulator location, homes above 80 psi, peak demand, and the questions to check
- NC State Extension: Inspecting a House — Slow toilet tank refill as a sign of low water pressure
- EPA WaterSense: Fix a Leak Week — Checking the water meter before and after two hours with no water use to find a leak
- Kohler: Leaking from End of Spout — Soaking an aerator in a 50/50 mix of warm water and white vinegar to dissolve hard water buildup
- HotWater.com: Why Your Water Heater Isn't Working — Home water pressure of 50 to 60 PSI and never above 80 PSI
General information, not professional advice. Conditions, codes and prices vary. Turn off power, gas or water before any work, and hire a licensed professional when in doubt. Cost figures are our estimates, not quotes.