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

Low water pressure usually comes from one of three places: a problem at the meter or main line (which you cannot fix), a clogged or failing pressure regulator (which you can replace), or mineral buildup in your pipes or fixtures (which you can clean). Before you call a plumber, check whether the problem is everywhere in your house or only at one sink or shower. If it is only one fixture, the fix is often as straightforward as cleaning the aerator. If it is everywhere, you are looking at either a regulator replacement or a call to your water company to check the meter.

The good news is that most pressure problems you can actually solve yourself cost under $30 in parts and take less than an hour. The key is figuring out where the problem lives—in one fixture, throughout your house, or in the water heater—because each location has a different fix.

Key Takeaways

  • Low pressure at a single faucet or showerhead usually means the aerator or showerhead screen is clogged with mineral deposits and can be cleaned or replaced for under $20.
  • Low pressure throughout your whole house points to a failing pressure regulator, which is a replaceable part that costs $50 to $150 in parts and can be swapped by a homeowner with basic tools.
  • If pressure is low only when you run hot water, the problem is likely sediment in your water heater, which requires draining the tank or calling a plumber.
  • Mineral buildup in supply lines cannot be cleared without professional equipment, so if cleaning fixtures does not help, contact your water company or a plumber to rule out meter or main-line issues first.

Clean the aerator on a single low-pressure faucet

An aerator is the small screen at the tip of your faucet that mixes air into the water stream. Over time, minerals from your water settle on this screen and block the flow. If only one faucet has low pressure, this is almost always the culprit.

Unscrew the aerator by hand or with a wrench if it is stuck. Soak it in white vinegar for 30 minutes to dissolve mineral deposits. Use an old toothbrush to scrub the screen gently, then rinse it under running water. Screw it back on. If the screen is damaged or still clogged after cleaning, replace it with a new one from any hardware store—they cost $3 to $8 and are universal.

If you cannot unscrew the aerator or the faucet still has low pressure after cleaning, the problem is inside the faucet body itself, and you will need a plumber to replace the valve cartridge or the entire faucet.

Clean or replace your showerhead

Showerheads clog the same way faucet aerators do. Unscrew the showerhead from the shower arm and soak it in a bag of white vinegar overnight. Use a toothbrush to scrub the holes where water comes out, then rinse and screw it back on.

If soaking does not work, you can drill out the holes carefully with a small drill bit, but it is usually easier and cheaper to buy a new showerhead for $10 to $30. If you replace it and pressure is still low, the problem is in the supply line to the shower, not the showerhead itself.

Check and replace your pressure regulator

A pressure regulator is a bell-shaped valve usually located where the main water line enters your house, often in the basement or crawlspace near the water meter. It keeps pressure from the street from spiking and damaging your pipes. If it fails, pressure drops throughout your whole house.

Look for a brass or plastic dome about 3 inches tall with a screw on top. If you find one and pressure is low everywhere, this is likely your problem. You can test it by attaching a pressure gauge (available at hardware stores for $10 to $20) to an outdoor faucet. Normal household pressure is 40 to 80 pounds per square inch. If your gauge reads below 40, the regulator may be failing.

Replacing a regulator requires shutting off the main water valve, unscrewing the old regulator, and screwing in a new one—a job most homeowners can do with a wrench and 30 minutes. Replacement regulators cost $50 to $150. If you are not comfortable doing this, a plumber can replace it in under an hour for a service call plus parts.

If you do not have a regulator, your water company is supplying pressure directly to your house. In that case, low pressure is a problem on their side of the meter, and you should contact them to report it.

Drain sediment from your water heater if only hot water is weak

If cold water pressure is normal but hot water pressure is low, sediment has likely built up inside your water heater tank. This is common in areas with hard water. The sediment blocks the outlet and restricts flow, making hot water come out slower than cold.

You can drain the tank yourself by attaching a garden hose to the drain valve at the bottom of the heater, turning off the cold water inlet, and opening the drain valve to let sediment flush out. This takes 30 to 45 minutes and costs nothing. However, if you are not comfortable working with your water heater, a plumber can do this for a service call fee, usually $100 to $200.

If draining does not help, the heating element itself may be clogged, and the heater may need replacement. You will know this is the case if pressure remains low after you have drained the tank completely and refilled it.

When to call your water company or a plumber

If you have cleaned all your aerators and showerheads, checked your pressure regulator, and pressure is still low everywhere in your house, the problem is likely at the meter or in the main line from the street. Call your water company and ask them to check the meter for leaks or blockages. This service is usually free, and they can tell you in one call whether the problem is on their side or yours.

If the water company finds no problem, or if you have low pressure at only one fixture that you cannot fix by cleaning, call a plumber. They can use a pressure gauge and flow test to pinpoint whether the issue is a failing valve, a kinked supply line, or mineral buildup deep in your pipes. Expect a service call to cost $100 to $200 before any repairs.

Frequently Asked Questions

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

Yes, but only slightly. The screw on top of the regulator adjusts the pressure setting. Turning it clockwise increases pressure; counterclockwise decreases it. However, do not raise pressure above 80 pounds per square inch, or you risk damaging pipes and fixtures. If you need to adjust it, turn the screw a quarter turn at a time and test with a pressure gauge.

Why is my water pressure low only in the morning?

This usually means the water company is doing maintenance on the main line early in the day, or pressure naturally drops during peak morning usage in your neighborhood. If it happens every morning and lasts more than an hour, contact your water company. If it clears up by mid-morning, it is likely a neighborhood issue, not your house.

Will a water pressure booster pump help?

A booster pump can increase pressure if your regulator is set too low or if the water company is supplying weak pressure. However, they cost $300 to $800 installed and require electricity. Before buying one, have a plumber confirm that low pressure is not caused by a clogged meter or a failing regulator, which are much cheaper to fix.

Is low water pressure a sign of a leak?

Not always, but it can be. If pressure dropped suddenly and your water bill went up, you likely have a leak in a supply line. Check your meter: turn off all water in the house, then look at the meter dial. If it moves, water is leaking somewhere. Call a plumber to locate it.

Can I fix low pressure by flushing my water heater myself?

Yes, if you are comfortable working with your water heater. Attach a hose to the drain valve, open it, and let water run until it runs clear. This takes 30 to 45 minutes. If you are unsure about the process or your heater is old, have a plumber do it to avoid damaging the tank or scalding yourself.