Low pressure usually comes from one of three places: the main shutoff valve, mineral buildup in aerators, or a problem at the meter or supply line

Before you call a plumber, check whether the problem is everywhere in your house or just one fixture. If only your kitchen sink is weak but the shower is fine, the issue is local—usually a clogged aerator. If pressure is low throughout the house, the culprit is either your main shutoff valve (partially closed by accident), mineral deposits in your pipes, or a leak or obstruction between your meter and your home. The first two you can fix yourself in minutes. The third requires a professional.

Start by checking your main shutoff valve, which is typically located near the water meter in a basement, crawl space, or outside in a box at the property line. If it is a gate valve (a valve with a wheel handle), turn it counterclockwise all the way until it stops—do not force it. If it is a ball valve (a lever handle), make sure the handle is parallel to the pipe, not perpendicular. Many homeowners accidentally close these partway and forget about it. This is the fastest fix and solves the problem in seconds.

Key Takeaways

  • Check your main shutoff valve first—a partially closed gate valve or ball valve is the most common cause of low pressure throughout the house.
  • Clean aerators (the screens at the end of faucet spouts) by unscrewing them and rinsing away mineral deposits, which restores pressure to individual fixtures.
  • If pressure is low everywhere and the shutoff valve is fully open, the problem is likely inside your pipes or at the meter, and you need a plumber.
  • Pressure regulators can be adjusted or replaced if your pressure is consistently too low, but this is a job for a licensed plumber in most places.

Clean the aerator on the affected faucet

If only one sink or faucet has weak pressure, the aerator is almost certainly the problem. An aerator is a small screen at the tip of the faucet spout that mixes air into the water stream. Over time, minerals from hard water build up on this screen and block the flow.

Unscrew the aerator by hand—most turn counterclockwise and come off easily. If it is stuck, wrap a cloth around it and use pliers, but turn gently to avoid damaging the threads. Once it is off, hold it under running water and rinse it thoroughly. If the screen is visibly clogged with white or tan deposits, soak it in white vinegar for 30 minutes to dissolve the mineral buildup, then rinse again and screw it back on. This usually restores full pressure to that fixture.

If the aerator is already clean or cleaning it does not help, the problem may be inside the faucet body itself. Mineral deposits can also build up in the valve cartridge or seat, which is more involved to fix. At that point, a plumber can either clean the internal parts or replace the cartridge.

Check for leaks or damage in visible supply lines

Walk around your home and look at any exposed water pipes—in basements, crawl spaces, under sinks, or in utility areas. Look for water stains, puddles, or wet spots on walls or floors. A leak between your meter and your home reduces the pressure that reaches your fixtures because water is escaping before it gets to you.

If you see obvious damage—a cracked pipe, a loose fitting, or active dripping—that is a sign you need a plumber. Do not try to patch a main supply line yourself. However, if you see a loose compression fitting (the kind with a nut that hand-tightens), you can try tightening it slightly with a wrench. Turn clockwise a quarter turn, then test the pressure. If that does not help or if you see no visible damage, the leak is likely underground or inside your walls, and a plumber will need to locate it.

Understand what a pressure regulator does and when to adjust it

Some homes have a pressure regulator, a bell-shaped device usually located on the main supply line near the meter or where the line enters the house. This device limits water pressure to protect your pipes and appliances from damage caused by pressure that is too high. If your regulator is set too low, it will reduce pressure throughout the house.

A pressure regulator has a screw on top that you can adjust. If you want to try raising the pressure, turn the screw clockwise a quarter turn, then test the pressure at a faucet. If it improves, you can turn it a bit more. Do not exceed 80 pounds per square inch (psi)—higher pressure can damage pipes, water heaters, and washing machines. Most homes run between 40 and 60 psi.

If you are not sure whether your home has a regulator, or if adjusting it does not help, call a plumber. In some jurisdictions, adjusting a regulator requires a licensed plumber, and a professional can also test your actual pressure with a gauge to tell you whether the regulator is the real problem.

Know when to call a plumber

Call a plumber if pressure is low everywhere in the house, the main shutoff valve is fully open, and you see no visible leaks. The problem is then either inside your pipes (mineral buildup in the main line, a partially collapsed pipe, or a blockage), at the meter, or in the supply line between the meter and your home. A plumber can test the pressure at different points to pinpoint where the problem is.

Also call a plumber if you suspect a leak but cannot find it, if you are uncomfortable adjusting the pressure regulator, or if cleaning aerators and checking the shutoff valve do not solve the problem. Low pressure that develops suddenly (rather than gradually over months) is more likely to be a leak or obstruction, which needs professional attention sooner rather than later.

Understand the difference between low pressure and low flow

Pressure is the force pushing the water, measured in psi. Flow is the volume of water coming out, measured in gallons per minute. They are related but not the same. A faucet can have good pressure (the water comes out hard) but low flow (not much volume), or vice versa.

If water comes out in a strong stream but there is not much of it, the problem is usually a clogged aerator or a partially closed shutoff valve. If water dribbles out weakly, the problem is low pressure. Knowing which one you have helps you and a plumber diagnose the issue faster. Most of the fixes in this guide address pressure, but they also improve flow in most cases.

Frequently Asked Questions

Can I increase water pressure by adjusting the pressure regulator myself?

You can try turning the adjustment screw clockwise a quarter turn and testing the result. However, many jurisdictions require a licensed plumber to adjust a regulator, and a professional can measure your actual pressure with a gauge to confirm whether the regulator is the problem. Do not exceed 80 psi, as higher pressure damages pipes and appliances.

What if pressure is low in just the hot water line?

The problem is likely in your water heater or the hot water supply line. Check whether the shutoff valve on the hot water line (usually on top of the heater) is fully open. If it is, sediment may have built up inside the heater, or there may be a leak in the hot line. A plumber can flush the heater or locate a leak.

How do I know if my water pressure is too low?

Normal household pressure is between 40 and 60 psi. If your shower feels weak, your washing machine fills slowly, or your outdoor hose barely sprays, pressure may be low. A plumber can measure it with a gauge. If you want to test it yourself, you can buy an inexpensive pressure gauge at a hardware store and screw it onto an outdoor faucet.

Will cleaning the aerator fix pressure everywhere in the house?

No. Cleaning an aerator only fixes pressure at that one faucet. If pressure is low throughout the house, the problem is the main shutoff valve, the pressure regulator, or something in the main supply line. Start by checking whether the shutoff valve is fully open.

What should I do if I find a leak in my supply line?

Do not try to patch a main supply line yourself. Call a plumber. If the leak is small and you need water in the meantime, you can wrap the area tightly with waterproof tape as a temporary measure, but this is not a permanent fix. A plumber will either repair or replace the damaged section.