Start by finding where the pressure drop happens

Low water pressure usually comes from one of three places: the main water line into your house, the pipes inside your walls, or a single fixture like a kitchen faucet. The fastest way to narrow it down is to check whether the problem is everywhere or just one sink or shower.

Turn on a faucet in your kitchen, then one in a bathroom, then a shower. If all three run weak, the issue is likely in your main line or the pipes feeding your whole house. If only one fixture is weak, the problem is almost certainly at that fixture itself — usually a clogged aerator or a closed shutoff valve.

You can also check your water meter if you have access to it (usually in the basement or outside near the street). If the meter is spinning fast even when no water is running, you have a leak somewhere in your main line. A steady spin means water is flowing out of your system even when everything is off.

Key Takeaways

  • Test multiple faucets to determine whether low pressure affects your whole house or just one fixture.
  • A clogged aerator — the screen at the faucet tip — is the most common cause and takes two minutes to clean.
  • A partially closed shutoff valve under a sink or in your basement can cut pressure to an entire section of your home.
  • Sediment buildup in your water heater reduces pressure to hot water only, and flushing the tank usually restores it.
  • If pressure is low everywhere and you see no obvious cause, call your water utility to check whether the problem is on their side of the meter.

Clean the aerator on a single weak faucet

The aerator is a small screen screwed onto the tip of your faucet. It mixes air into the water stream and prevents splashing, but it also catches sediment and mineral deposits. If only one faucet is weak, this is almost always the culprit.

Unscrew the aerator by hand — it usually twists off counterclockwise. If it is stuck, wrap a cloth around it and use pliers, but turn gently to avoid stripping the threads. Once it is off, hold it up to the light. You should see a fine mesh screen. If it looks discolored or clogged, soak it in white vinegar for 30 minutes to dissolve mineral buildup.

While it soaks, run water from the faucet without the aerator. If pressure suddenly jumps, the aerator was definitely the problem. After soaking, rinse the aerator under running water and use an old toothbrush to scrub the screen gently. Screw it back on and test. If pressure is still low, the problem is deeper in the faucet itself or in the shutoff valve underneath.

Check the shutoff valve under the sink or in your basement

Every fixture has a shutoff valve — a small knob or lever underneath the sink or where the water line enters your house. These valves can be partially closed without you realizing it, cutting off water to that fixture or to your entire home.

Look under your kitchen and bathroom sinks. You should see two small valves (one for hot, one for cold) where the water lines connect. Turn both fully counterclockwise — they should spin freely and stop after a few turns. If one is only halfway open, that is your problem. Do the same for the main shutoff valve in your basement or crawlspace, usually near where the water line enters from the street.

If a valve is stuck or will not turn, do not force it. Stuck valves can break, and a broken main shutoff means you cannot stop water in an emergency. Call a plumber instead. If all valves are fully open and pressure is still low everywhere, move to the next step.

Flush your water heater if only hot water is weak

If cold water pressure is normal but hot water comes out weak, sediment has built up inside your water heater tank. This is common in areas with hard water. Flushing the tank usually restores pressure in 30 minutes to an hour.

First, turn off the power to your water heater. If it is electric, flip the breaker. If it is gas, turn the dial to "Pilot." Wait 30 minutes for the tank to cool slightly. Locate the drain valve at the bottom of the tank — it looks like a small faucet. Attach a garden hose to it and run the hose to a floor drain or outside. Open the valve slowly and let water drain for 5 to 10 minutes. You may see brown or cloudy water; that is sediment leaving the tank.

Close the drain valve, turn the power back on, and wait for the tank to refill and reheat. This usually takes 30 to 60 minutes depending on tank size. Once it is hot again, test a hot water faucet. Pressure should improve noticeably. If it does not, sediment may be clogging the outlet pipe inside the tank, and you will need a plumber to descale it properly.

Look for leaks in visible pipes

A leak in your main water line or in pipes running through your basement or crawlspace can reduce pressure throughout your home. Walk through your basement and look for wet spots on the floor, walls, or pipes. Check around the water meter and where the main line enters your house.

Even a small pinhole leak wastes water and drops pressure. If you spot dampness or water pooling, mark the location and call a plumber. Do not try to patch a main line yourself — these require professional tools and permits in most areas.

If you suspect a leak but cannot see one, watch your water meter. Write down the number, wait two hours without using any water, then check again. If the number has changed, you have a leak somewhere. This is worth reporting to a plumber because hidden leaks can damage your foundation or create mold.

Contact your water utility if pressure is low everywhere

If you have ruled out shutoff valves, clogged aerators, and leaks, the problem may be on your water utility's side of the meter. Water pressure can drop due to main line breaks, high demand during peak hours, or maintenance work in your neighborhood.

Call your water utility's customer service number (usually on your bill) and report low pressure. They can check the pressure at the meter and tell you whether the issue is in their system or yours. If it is theirs, they will investigate and may send a crew to repair the main line. If it is yours, they can confirm that your meter is receiving normal pressure, which means the problem is in your home's plumbing.

Some utilities offer free pressure tests. Ask whether yours does. If pressure at the meter is normal but weak inside your home, you likely have sediment buildup in your main shutoff valve or in the pipes themselves. A plumber can install a sediment filter or flush your lines to restore pressure.

When to call a plumber

Call a plumber if you have checked aerators, shutoff valves, and the water heater and pressure is still low. Also call if you find a leak, if a shutoff valve is stuck, or if your utility confirms that pressure at the meter is normal but your home's pressure is weak.

A plumber can use a pressure gauge to measure the exact pressure at different points in your system, pinpoint where the drop occurs, and recommend repairs. They can also flush your main line, replace corroded pipes, or install a pressure regulator if your utility's pressure is too high (which can damage fixtures over time).

If you rent, contact your landlord or property manager instead of calling a plumber yourself. They are responsible for maintaining the water system, and you should not pay for repairs to the building's plumbing.

Frequently Asked Questions

Why is my water pressure low only in the morning?

Morning pressure dips are usually caused by high demand in your neighborhood — many people showering and using water at the same time. This is normal and typically resolves within an hour. If it happens every morning and lasts all day, call your utility to check whether there is a main line issue or maintenance work in your area.

Can I increase water pressure myself?

You can clean aerators and check shutoff valves yourself. If your utility's pressure is lower than normal, you can install a pressure booster pump, but this requires a plumber and a permit in most areas. Do not adjust the pressure regulator on your main line without professional help — too much pressure damages pipes and fixtures.

What is normal water pressure?

Normal residential water pressure is 40 to 60 pounds per square inch (PSI). You can check yours with an inexpensive pressure gauge screwed onto an outdoor faucet. If your pressure is consistently below 40 PSI and your utility confirms their pressure is normal, you have a problem in your home's plumbing that a plumber should inspect.

Does hard water cause low pressure?

Hard water causes mineral buildup that can clog aerators and reduce pressure over time, especially in hot water lines. Flushing your water heater and cleaning aerators regularly helps. If buildup is severe, a water softener can prevent future mineral deposits, but it does not restore pressure that is already lost.

Is low water pressure dangerous?

Low pressure itself is not dangerous, but it can indicate a leak or a problem with your water heater. If pressure drops suddenly and you cannot find the cause, have a plumber check for leaks in your main line. A hidden leak can damage your foundation or create conditions for mold growth.