Start with the simplest fixes first

Low water pressure often comes from something you can fix yourself in minutes. Before you call a plumber, check whether the problem is everywhere in your house or only in one room. If it is only one faucet or shower, the issue is almost always a clogged aerator — the screen at the tip of the faucet — or a partially closed shut-off valve under the sink. Unscrew the aerator, rinse it under running water to clear mineral buildup, and screw it back on. If that does not work, turn the shut-off valve under the sink all the way counterclockwise (open). These two steps solve the majority of single-fixture problems.

If low pressure affects your whole house, check the main shut-off valve where the water line enters your home. It should be fully open — turned all the way counterclockwise. A partially closed valve cuts pressure throughout the house and is often left that way by accident after plumbing work. Also check whether you have a pressure regulator (a bell-shaped fitting on the main line) and whether it has an adjustment screw on top. If the screw is turned too far clockwise, it reduces pressure to the whole house. Loosen it slightly and test your pressure again.

Key Takeaways

  • Clogged aerators and partially closed shut-off valves under individual sinks cause low pressure in one faucet or shower and take minutes to fix.
  • A main shut-off valve that is not fully open or a pressure regulator set too low reduces pressure throughout your entire house.
  • Mineral buildup in your pipes or water heater, or a failing check valve, requires a plumber but is not an emergency.
  • Water pressure below 40 pounds per square inch (psi) may indicate a problem with your municipal supply or a leak in your line.
  • A pressure gauge costs under $15 and lets you measure your actual pressure before deciding whether to call a professional.

Measure your water pressure with a gauge

A water pressure gauge costs $10 to $20 at any hardware store and screws onto an outdoor faucet or a hose bib in seconds. Turn on the faucet fully and read the number on the dial. Normal household pressure is 40 to 80 psi (pounds per square inch). If your reading is below 40 psi, you have a real problem. If it is between 40 and 80 psi but feels weak, the issue may be that you are used to higher pressure or that flow is being split among multiple fixtures.

A pressure gauge also tells you whether the problem is on your side of the meter or the water company's side. If pressure is low at the meter but normal at the street (where the main line enters your property), the problem is in your home's plumbing. If pressure is low at the street, call your water company — the issue is in their line or at the treatment plant, and you cannot fix it yourself.

Clear mineral buildup in your pipes and water heater

Over time, minerals from hard water build up inside pipes and reduce the space water can flow through. This happens slowly and affects pressure throughout the house. If you have lived in your home for many years and pressure has gradually declined, mineral buildup is a likely cause. The water heater is a common culprit because hot water carries more minerals and deposits them faster than cold water does.

Flushing your water heater can restore some pressure. Turn off the heater, attach a garden hose to the drain valve at the bottom, and let water run into a bucket or drain until it runs clear. This removes sediment that collects at the bottom. For pipes themselves, a plumber can use a hydro-jetting service to blast mineral deposits out, though this is expensive and usually only worth doing if pressure is very low. A water softener prevents future buildup but requires installation and ongoing maintenance.

Check for leaks in your main line

A leak between your meter and your house reduces pressure because water escapes before it reaches your fixtures. Signs of a leak include a wet spot in your yard that does not dry after rain, a hissing sound near the meter, or a sudden spike in your water bill. To check for a leak, turn off all water in your house and look at your meter. If the number keeps rising, water is leaking somewhere in your line.

A leak in the main line requires a plumber to locate and repair. The cost depends on how deep the line is buried and where the leak is. If the leak is between the meter and your house, your water company may cover part of the repair cost — ask them before you hire anyone. Do not ignore a leak, because it wastes water and can damage your foundation or yard.

Replace a failing check valve or backflow preventer

A check valve is a one-way fitting that prevents water from flowing backward through your pipes. If it fails, water can flow in both directions, which reduces forward pressure. A backflow preventer serves a similar purpose and is required by code in many areas. Both are usually located on the main line near the meter.

If a plumber suspects a failing check valve, they can test it by measuring pressure before and after the valve. Replacing one costs $150 to $300 and takes an hour. This is not something you can do yourself unless you have plumbing experience, because it requires shutting off the main line and working with fittings that need to be sealed properly.

Install a pressure booster pump if pressure is chronically low

If your water company delivers pressure below 40 psi consistently, or if you live on a hill where gravity reduces pressure, a pressure booster pump can help. This device sits on your main line and uses a motor to increase pressure throughout your house. A basic booster pump costs $300 to $800 installed and uses electricity to run. It is a permanent solution but requires professional installation and occasional maintenance.

Before you buy a booster pump, confirm with your water company that low pressure is normal in your area and not a temporary problem. Some municipalities have low pressure in certain zones during peak hours but normal pressure at night. A booster pump is worth the cost only if low pressure is constant and affects your daily life — for example, if showers are unusable or washing machines run slowly.

Know when to call a plumber

Call a plumber if pressure is low throughout your house and you have already checked the main shut-off valve and pressure regulator. Also call if you suspect a leak, if pressure dropped suddenly without an obvious cause, or if you have measured pressure and it is below 40 psi. A plumber can diagnose the problem in an hour and tell you what repair costs. Many plumbers charge $100 to $200 for a service call, which is worth paying to avoid guessing.

Do not attempt to repair the main line, pressure regulator, or check valve yourself unless you have done plumbing work before. These fittings are under pressure and can leak or burst if not sealed correctly. A bad repair can cost more to fix than hiring a professional from the start.

Frequently Asked Questions

Why is my water pressure high in the morning and low in the afternoon?

This usually means your water company reduces pressure during peak hours when demand is high. It is normal and not a problem with your home. If pressure is still above 40 psi in the afternoon, you do not need to do anything. If it drops below 40 psi, contact your water company to ask whether they have a pressure issue in your area.

Can I increase water pressure by adjusting my pressure regulator?

Yes, if you have a regulator. Locate the adjustment screw on top of the bell-shaped fitting on your main line. Turn it counterclockwise to increase pressure, clockwise to decrease it. Make small quarter-turn adjustments and test pressure with a gauge after each one. Do not exceed 80 psi, because higher pressure can damage pipes and appliances.

Does a water softener improve water pressure?

A water softener does not increase pressure, but it prevents mineral buildup that reduces pressure over time. If you already have low pressure from existing mineral deposits, a softener will not fix it — you need to flush your water heater or hire a plumber to clean your pipes. A softener only stops future buildup.

What should I do if my neighbor has good pressure but I do not?

This suggests the problem is in your home's plumbing, not the municipal supply. Check your main shut-off valve, pressure regulator, and aerators. Measure pressure at your meter to confirm it is low. If pressure at the meter is normal but low at your fixtures, you have a leak or mineral buildup in your line — call a plumber to locate it.

Is low water pressure a health hazard?

Low pressure itself is not a health hazard, but it can allow contamination to enter your pipes if pressure drops below 20 psi. If you notice pressure dropping suddenly, boil water until a plumber confirms there is no contamination. Pressure below 20 psi is rare and usually means a major leak or a problem at the water treatment plant.