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

Low water pressure usually comes from one of three places: a problem inside your home that you can address, a problem between your meter and your home that requires a plumber, or a problem with your water company's main line that you cannot fix. Before you call anyone, check whether the problem is everywhere in your house or only at one fixture—that tells you when ready which category you are in.

If only one sink or shower has low pressure, the blockage is in that fixture's supply line or the fixture itself. If the whole house has low pressure, the problem is either your main shut-off valve, your pressure regulator, sediment in your meter, or your water company's service line. Start with the simplest checks: is your main shut-off valve (usually near your water meter) fully open? A valve that is only partially open will cut pressure throughout the house. Turn it counterclockwise until it stops—do not force it.

Key Takeaways

  • Low pressure at one fixture usually means a clogged aerator or mineral buildup in that faucet or showerhead, which you can clean in minutes.
  • Low pressure everywhere in the house points to your main shut-off valve, pressure regulator, or water meter sediment—all things a plumber can diagnose in one visit.
  • If your water company's main line is the problem, you cannot fix it yourself, but the water department will tell you that when you call.
  • Cleaning aerators and showerheads costs nothing and solves the problem about half the time pressure drops suddenly at a single fixture.

Clean the aerator on the affected faucet

The aerator is the small screen at the tip of your faucet. Mineral deposits and sediment collect there and restrict flow. Unscrew it by hand (turn counterclockwise) or wrap it in a cloth and use pliers if it is stuck. Soak it in white vinegar for 30 minutes to dissolve mineral buildup, then scrub it with an old toothbrush and rinse it thoroughly.

While the aerator is soaking, run water from that faucet without it. If pressure suddenly improves, the aerator was the problem—reinstall it after cleaning. If pressure stays low, the blockage is deeper in the supply line and you will need a plumber. Showerheads work the same way: unscrew them, soak in vinegar, scrub, and reinstall.

Check your pressure regulator if the whole house is affected

Most homes have a pressure regulator—a bell-shaped or cylindrical device on the main water line, usually near your meter. It keeps water pressure from getting too high and damaging your pipes. If it fails or gets stuck, it can reduce pressure throughout the house. You cannot repair it yourself, but you can tell if it is the problem by calling a plumber for a pressure test.

A plumber will attach a gauge to an outdoor faucet and measure your incoming pressure. If it is below 40 pounds per square inch (psi), your regulator may be failing. If it is above 80 psi, your regulator is not doing its job. Normal household pressure is 50 to 80 psi. Replacing a regulator costs between $300 and $500 in most areas, but a plumber can confirm whether that is what you need.

Look for sediment in your water meter

Sediment and mineral buildup can collect inside your water meter, especially in older homes or areas with hard water. This is not something you can clean yourself—the meter is sealed and owned by your water company. However, you can ask your water company to flush the meter or inspect it for sediment.

Call your water utility and describe the problem: low pressure everywhere, no leaks visible, and the main shut-off valve is fully open. They may send someone to check the meter at no cost. If sediment is the issue, they will clean or replace the meter. This is worth doing before you pay a plumber, because if the meter is the problem, a plumber cannot fix it.

Rule out a problem on the water company's side

If your whole house has low pressure and your shut-off valve is open, ask your neighbors whether they have the same problem. If they do, the issue is on your water company's main line—a break, a valve problem, or high demand in your area. Call your water utility and report it. They will investigate and repair it at no cost to you.

If your neighbors have normal pressure, the problem is between the main and your home. This is your responsibility, not the water company's. A plumber can trace the line and find leaks or blockages. If there is a leak, you will also see wet spots in your yard or higher-than-normal water bills.

When to call a plumber

Call a plumber if cleaning aerators does not help, if pressure is low everywhere in the house, or if you suspect a leak. A plumber can run a pressure test, inspect your regulator, check for leaks in your main line, and recommend whether you need repairs. Most plumbers charge $100 to $200 for a service call and diagnosis.

Before the plumber arrives, write down exactly where the pressure is low (one fixture or the whole house), when it started, and whether anything changed recently (new appliance, recent work on your pipes, or a sudden spike in your water bill). This information helps the plumber narrow down the cause.

Frequently Asked Questions

Can I increase my water pressure by adjusting something myself?

If you have a pressure regulator, there is usually an adjustment screw on top, but do not turn it without knowing your current pressure. Turning it the wrong way can damage your pipes or make the problem worse. Have a plumber test your pressure first and adjust the regulator if needed.

Why did my water pressure drop suddenly?

Sudden pressure loss usually means a blockage in a single fixture (clean the aerator), a leak in your main line (check for wet spots or a high water bill), or a problem at your water meter or regulator. If it happened after plumbing work, air in the lines can cause low pressure—run cold water from the lowest faucet in your house for a few minutes to bleed the air out.

Does hard water cause low pressure?

Hard water causes mineral buildup in aerators and showerheads, which reduces pressure at those fixtures. It can also build up inside pipes over decades, but that is rare in homes less than 30 years old. Cleaning aerators solves the problem in most cases.

How much does it cost to fix low water pressure?

Cleaning an aerator costs nothing. A plumber's service call and diagnosis runs $100 to $200. Replacing a pressure regulator costs $300 to $500. Fixing a leak in your main line varies widely depending on where the leak is and whether your yard has to be dug up.

What if low pressure is only in my hot water?

Low hot water pressure usually means sediment buildup in your water heater. Drain your water heater by attaching a hose to the drain valve at the bottom and running it outside or into a bucket. Do this once a year to prevent buildup. If draining does not help, the heater may need replacement.