Where the problem usually starts

Low water pressure at your tap usually comes from one of three places: a problem inside your home's plumbing, a problem between your meter and your home, or a problem at the water main. The fastest way to narrow it down is to check whether the low pressure affects your whole house or just one room.

If only one faucet or shower has weak pressure, the blockage is almost certainly inside that fixture or the pipe feeding it. If the whole house is affected, the issue is either in your main water line, at your meter, or at the street supply. Call your water company's non-emergency line to ask whether they are doing work in your area or whether pressure is low on the street — they can tell you in seconds, and it saves you from tearing into your walls for nothing.

Key Takeaways

  • Low pressure in one fixture usually means a clogged aerator or mineral buildup inside that faucet, which you can clean in minutes without tools.
  • Low pressure throughout the house points to a problem in your main water line, at your meter, or at the street supply — call your water company first to rule out their side.
  • A partially closed shut-off valve at your meter or under the sink is an straightforward fix that solves whole-house pressure loss in seconds.
  • Sediment buildup in your water heater can reduce pressure to hot-water fixtures only, and flushing the tank usually restores it.
  • Pinhole leaks in copper pipes are rare but serious, and they require a plumber because the leak is usually hidden inside a wall.

Cleaning the aerator on a single faucet

The aerator is the small screen at the tip of your faucet. It mixes air into the water stream and catches sediment and mineral deposits. When it clogs, pressure drops at that one tap while everywhere else works fine.

Unscrew the aerator by hand or with a wrench if it is stuck. Rinse it under a strong stream of water, then soak it in white vinegar for 30 minutes to dissolve mineral buildup. Use an old toothbrush to scrub the screen, rinse it again, and screw it back on. If the pressure returns, you are done. If it does not, the clog is deeper in the faucet or the supply line to that fixture, and you may need a plumber.

Checking the shut-off valves

Your home has a main shut-off valve where the water line enters from the street, usually in a basement, crawl space, or utility closet. It also has a shut-off valve under each sink. If either valve is only partially open, it will restrict pressure to that fixture or the whole house.

Locate your main shut-off valve and check that the handle is parallel to the pipe (fully open). If it is perpendicular, turn it until it is parallel. Do the same for the shut-off valve under any sink with low pressure. This takes 10 seconds and solves the problem in many cases. If the valve is stuck or will not turn, do not force it — call a plumber, because forcing it can break the valve and create a leak.

Flushing sediment from your water heater

If only your hot water has low pressure and your cold water is fine, sediment inside your water heater is the likely cause. Over time, minerals settle at the bottom of the tank and can block the outlet pipe.

Turn off the power to your water heater (switch off the breaker for electric, or turn the gas valve to pilot for gas). Attach a garden hose to the drain valve at the bottom of the tank and run it to a floor drain or outside. Open the drain valve and let the tank empty completely — this takes 30 minutes to an hour. Close the drain valve, turn the power back on, and refill the tank by opening a hot-water faucet until water runs clear. Pressure should return. If it does not, the blockage is in the outlet pipe itself, and a plumber will need to replace or bypass it.

Looking for leaks in your main water line

A leak in the pipe between your meter and your house will reduce pressure throughout the home and waste water. The leak is usually underground or inside a wall, so you cannot see it directly, but you can spot the signs: wet patches in your yard, a hissing sound near the meter, or a sudden spike in your water bill.

If you suspect a leak, turn off all water-using appliances and faucets, then look at your water meter. If the meter is still spinning or the numbers are still climbing, water is leaking somewhere. Call a plumber — they have equipment to locate the leak without digging up your whole yard. Pinhole leaks in copper pipes are the most common cause, and they require the affected section of pipe to be replaced or bypassed.

Checking for mineral buildup in pipes

In areas with hard water, minerals can accumulate inside your pipes over years and gradually reduce pressure. This happens slowly and affects the whole house, not just one fixture. You cannot clean the inside of buried pipes yourself, but a plumber can flush your system with a chemical solution designed to dissolve mineral deposits.

Before calling a plumber, confirm that the problem is not something simpler — check your shut-off valves, clean your aerators, and call your water company to rule out street-side issues. If pressure is still low everywhere and you have hard water, mineral buildup is worth investigating. The cost of a flush is usually between $300 and $500, depending on your plumber and the size of your system.

When to call a plumber

You can handle aerator cleaning and shut-off valve checks yourself. Everything else — leaks in the main line, blockages deep in the plumbing, water heater issues, or mineral buildup in pipes — requires a licensed plumber. Get at least two quotes before you commit, and ask whether the plumber will diagnose the problem for a flat fee or charge hourly. Some plumbers will waive the diagnostic fee if you hire them for the repair.

If your water company has ruled out problems on their side and you have checked the obvious fixes, a plumber can usually pinpoint the issue in one visit. Pressure problems that come on suddenly are often easier to fix than ones that develop slowly, because sudden problems are usually mechanical (a stuck valve, a new leak) rather than chemical (mineral buildup).

Frequently Asked Questions

Why is my water pressure low only in the morning?

Morning pressure dips often happen because your water company is flushing the main line or because demand is highest when everyone showers at once. If pressure returns to normal by mid-morning, it is a supply-side issue and not your problem. If it stays low all day, the issue is in your home or meter.

Can a water softener fix low pressure?

A water softener does not fix existing low pressure, but it can prevent mineral buildup from making pressure worse over time. If you already have low pressure from mineral deposits, you need a system flush first. A softener helps after that.

Does low water pressure mean I have a leak?

Not always. Low pressure can come from a partially closed valve, a clogged aerator, sediment in your water heater, or a problem at the street supply. A leak is one possibility, but check the simpler things first. If your water bill is normal and your yard is dry, a leak is unlikely.

How much does it cost to fix low water pressure?

Cleaning an aerator costs nothing. Replacing a shut-off valve runs $150 to $300. Flushing a water heater costs $200 to $400. Finding and repairing a main line leak can run $1,000 to $3,000 depending on location and severity. Get a quote from your plumber before work starts.

Is low water pressure a sign of a serious problem?

Not always. A clogged aerator or a stuck valve is annoying but not serious. A leak in your main line or pinhole corrosion in copper pipes is serious because it wastes water and can damage your foundation. Call a plumber if pressure drops suddenly or if you see signs of a leak.