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

Low water pressure usually starts at one of three places: your water meter valve, your pressure regulator, or a clogged aerator. The meter valve and regulator are outside your home or in a basement; the aerators are the screens at the end of your faucets. You can adjust or clean these yourself in under an hour. If pressure is low everywhere in the house, start with the meter valve and regulator. If it's low at only one or two faucets, the problem is almost certainly a clogged aerator.

Before you start, turn off the main water supply to your home. You'll find the shutoff valve where the water line enters your house—usually in the basement, crawlspace, or outside near the foundation. Turn the handle clockwise until it stops. Then open a faucet on the lowest floor to release pressure in the pipes.

Key Takeaways

  • The water meter shutoff valve and pressure regulator are the first places to check when pressure is low throughout the house.
  • A clogged faucet aerator—the screen at the tip of the spout—causes low pressure at a single faucet and takes five minutes to clean.
  • The pressure regulator should be set between 40 and 80 pounds per square inch; you can adjust it with a wrench if you locate it in your basement or under the sink.
  • Mineral buildup in old pipes and leaks elsewhere in the system can lower pressure, and both require a plumber to diagnose.
  • If pressure is low only when you run hot water, the problem is in your water heater, not your main supply.

Check and adjust the water meter shutoff valve

The water meter shutoff valve controls flow from the street into your home. If it's partially closed, pressure drops everywhere. Find your water meter—usually in the basement, a crawlspace, or an underground box outside near the street. The valve is a handle or knob attached to the pipe just before or after the meter.

Turn the handle counterclockwise as far as it will go. If it was partially closed, you should feel resistance and then a release as it opens fully. Turn on a faucet upstairs to check whether pressure improves. If the valve is stuck or won't turn, do not force it—call a plumber, because forcing it can break the valve and leave you without water.

Locate and adjust your pressure regulator

A pressure regulator is a bell-shaped or cylindrical device that sits on the main water line, usually within three feet of where water enters your home. It keeps pressure from the street from damaging your pipes and fixtures. If it's set too low, your faucets and showers will feel weak. If it's set too high, you'll hear banging in the pipes and fixtures will wear out faster.

The regulator has a screw on top or a bolt on the side. You'll need an adjustable wrench. Before you adjust it, screw a pressure gauge onto a hose bib (outdoor faucet) or buy an inexpensive gauge at a hardware store. Turn on the hose bib and read the pressure. It should be between 40 and 80 pounds per square inch. If it's below 40, turn the adjustment screw or bolt counterclockwise a quarter turn, wait 30 seconds, and check the gauge again. Repeat until you reach 50 to 60 psi. Do not exceed 80 psi.

If you cannot find the regulator, it may not be installed—some homes don't have one. If you adjust it and pressure doesn't change, the regulator may be faulty and will need replacement by a plumber.

Clean clogged faucet aerators

An aerator is a small screen at the tip of a faucet spout. It mixes air into the water stream and prevents splashing. Mineral deposits and debris clog it over time, making that faucet feel weak while others work fine. Cleaning takes five minutes.

Unscrew the aerator by hand or with a wrench if it's tight. Hold it up to the light—if you see white, tan, or rust-colored buildup, that's the problem. Soak it in white vinegar for 30 minutes to dissolve mineral deposits. Use an old toothbrush to scrub the screen and the inside of the aerator. Rinse it thoroughly under running water, then screw it back on. If the screen is damaged or won't come clean, replace it with a new one from a hardware store for a few dollars.

Check for leaks in your supply lines

A leak anywhere in your main supply line—from the meter to your fixtures—reduces pressure throughout the house. Look under sinks, in the basement, and in crawlspaces for wet spots, stains, or the sound of running water when all faucets are off. Check the water meter: if the dial moves when nothing is running, you have a leak.

Small leaks at connection points sometimes stop on their own as mineral deposits seal them. If a leak is actively dripping or spraying, you can try tightening the connection with a wrench—turn clockwise, a quarter turn at a time. If tightening doesn't stop it or if you see water pooling, call a plumber. Leaks in buried supply lines require professional detection and repair.

Understand why hot water pressure is different from cold

If cold water pressure is normal but hot water pressure is weak, the problem is in your water heater, not your main supply. The most common cause is mineral buildup inside the heater's dip tube—the pipe that carries cold water to the bottom of the tank. As it clogs, less cold water enters, and the heater can't produce enough hot water at normal pressure.

You can try flushing the water heater by attaching a hose to the drain valve at the bottom and running water through it into a bucket or floor drain for a few minutes. This sometimes clears light buildup. If pressure doesn't improve, the dip tube may need replacement, which requires a plumber. Do not attempt to open the heater itself.

When to call a plumber

Call a plumber if pressure remains low after you've checked the meter valve, adjusted the regulator, and cleaned aerators. You may have a leak in a buried line, a failed regulator, mineral buildup in old galvanized pipes, or a problem with the water heater that requires professional diagnosis.

Also call a plumber if the meter valve is stuck, if you cannot locate the pressure regulator, or if you hear banging or whistling in the pipes—these are signs of pressure problems that need professional attention. A plumber can test pressure at different points in your system to pinpoint where the loss is happening.

Frequently Asked Questions

Can low water pressure damage my pipes or appliances?

Low pressure itself doesn't damage pipes, but it can be a sign of a leak that does. If pressure is too high—above 80 psi—it stresses connections and can shorten the life of fixtures and appliances. A regulator keeps pressure in the safe range.

Why is my water pressure low only in the morning?

Morning low pressure often happens because the water company is doing maintenance on the street, or because your neighborhood's demand is highest then. It usually returns to normal within an hour. If it happens every morning, call your water company to ask whether they're doing work in your area.

Will increasing water pressure reduce my water bill?

No. Pressure and flow are different. Higher pressure doesn't mean more water is flowing—it means the water is moving faster. Your bill is based on volume, not speed. Increasing pressure won't lower your bill.

Is it safe to adjust the pressure regulator myself?

Yes, adjusting the screw or bolt is safe. You're not opening the device or touching internal parts—you're just turning an adjustment screw. Use a wrench, turn slowly, and check your progress with a pressure gauge. If you're uncomfortable, a plumber can do it in 15 minutes.

What if my house has no pressure regulator?

Some homes don't have one, especially older ones. If your pressure is consistently above 80 psi, a plumber can install a regulator. If pressure is normal and stable, you may not need one. A plumber can test your pressure and advise whether installation would help.