Where low water pressure comes from and what you can fix yourself

Low water pressure usually comes from one of three places: a closed or partially closed valve, a clogged aerator or screen, or sediment buildup in your pipes. The first two you can fix in minutes. The third takes longer but is still something you can handle without calling a plumber—though sometimes the problem is in the water main or your meter, which means you need professional help.

Start by checking whether the low pressure is everywhere in your house or only at one fixture. If it's only one sink or shower, the problem is local—an aerator or showerhead screen. If it's everywhere, look for a valve you can adjust yourself.

Key Takeaways

  • Check the main water shut-off valve and the meter valve—both should be fully open, and a partially closed valve is the fastest fix for low pressure everywhere.
  • Unscrew and clean the aerator (the screen at the faucet tip) or showerhead screen, which often trap sediment and debris that block flow.
  • Sediment buildup inside pipes can be flushed by opening the lowest faucet in your house and letting water run for several minutes.
  • If pressure is low only at hot water taps, the problem is usually in your water heater and may need a professional to drain and flush.
  • Water pressure that drops suddenly after years of normal flow often means a leak somewhere in your system, and you should check your water meter to confirm.

Check your main shut-off valve and meter valve

Your main water shut-off valve is usually in the basement, crawlspace, or outside near the street. It looks like a gate valve (a wheel handle) or a ball valve (a lever handle). If it's a gate valve and the handle is only halfway open, turn it counterclockwise all the way open. If it's a ball valve, the handle should be parallel to the pipe—if it's perpendicular, the valve is closed.

Next, locate your water meter. It's usually in the same area as the shut-off valve or outside in a meter box. There's often a second valve right next to the meter. Check that this one is also fully open using the same rule: gate valves turn counterclockwise to open, ball valves should have the handle parallel to the pipe.

A partially closed valve is the most common reason for low pressure in the whole house, and opening it takes seconds. If both valves are already fully open, move on to the next step.

Clean aerators and showerhead screens

An aerator is the small screen at the tip of a faucet. Sediment, mineral deposits, and debris collect there and restrict flow. Unscrew the aerator by hand (turn counterclockwise) or use a wrench if it's stuck. Rinse it under running water and use an old toothbrush to scrub away any buildup. If you see heavy white or tan deposits, soak it in white vinegar for 30 minutes, then scrub again.

Showerheads work the same way. Unscrew the showerhead from the shower arm, rinse it, and scrub the holes with a toothbrush. For heavy mineral buildup, soak the showerhead in a bag of white vinegar tied around the shower arm overnight, then scrub and rinse.

Screw the aerator or showerhead back on by hand until it's snug—do not overtighten. Turn the water back on and check the pressure. This fix solves low pressure at a single fixture about 80 percent of the time.

Flush sediment from your pipes

Sediment inside your pipes reduces flow throughout the house. You can flush some of it out by opening the lowest faucet in your home (usually a basement sink or outdoor hose bib) and letting cold water run hard for 5 to 10 minutes. This stirs up sediment and pushes it out. The water may look cloudy or discolored at first—that's normal.

If you have a whole-house water filter, check whether it needs replacing. A clogged filter looks like a cartridge inside a canister under the sink or in the basement. If the filter is visibly dirty or you cannot remember when it was last changed, replace it according to the manufacturer's instructions. A new filter often restores pressure noticeably.

If flushing and filter replacement do not help, sediment may be deeper in your pipes. This is harder to clear without professional equipment, so contact a plumber if pressure remains low.

Check whether the problem is your water heater

If pressure is low only when you use hot water, the issue is in your water heater, not your main supply. Water heaters collect sediment at the bottom over time, which reduces the space for water and slows flow. You can drain and flush your water heater yourself, though it takes an hour and requires caution around hot water.

Turn off the power to the heater (flip the breaker for electric, or turn the gas knob 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 is hot water, so be careful. Once empty, close the drain valve, turn the cold water inlet valve on and off a few times to flush sediment, then refill the tank and restore power.

If you are not comfortable doing this, a plumber can flush your water heater in about an hour. If pressure is still low after flushing, the heater may be failing and need replacement.

When to call a plumber

Call a plumber if pressure drops suddenly after years of normal flow, because this usually means a leak somewhere in your system. You can check by reading your water meter: turn off all water in the house, note the meter reading, wait 30 minutes without using water, and read it again. If the number changed, you have a leak.

Also call a plumber if low pressure is everywhere in the house and both your main valve and meter valve are fully open. The problem may be in the water main, at your meter, or in a hidden section of pipe—all things that need professional diagnosis and repair.

If pressure is low only at hot water taps and flushing the water heater does not help, the heater itself may be failing. A plumber can determine whether it needs repair or replacement.

Frequently Asked Questions

Can low water pressure damage my pipes or appliances?

Low pressure itself does not damage pipes, but the sediment that causes it can. Sediment also clogs washing machine inlet screens and reduces the life of water heaters. Fixing low pressure early prevents these problems from getting worse.

Why is my water pressure low only in the morning?

Morning pressure dips are common when demand is high across your neighborhood. If pressure returns to normal later in the day, this is a water company issue, not a problem in your house. If it stays low all day, follow the steps above.

Will a pressure regulator help if my pressure is too low?

A pressure regulator reduces high pressure, not low pressure. If your pressure is below 40 pounds per square inch (psi), a regulator will not help. You need to fix the underlying cause—a closed valve, clogged aerator, or sediment buildup.

How often should I clean my faucet aerators?

Clean aerators once a year or whenever you notice low pressure at that fixture. In areas with hard water or older homes with sediment in the pipes, you may need to clean them more often.

What if I open my main valve all the way and pressure is still low?

Check your meter valve next. If both are fully open and pressure is still low everywhere, the problem is likely in the water main, at your meter, or in a hidden leak. Contact your water company first to rule out a main-line issue, then call a plumber if they find no problem on their end.