Start with the simplest fixes first

Low water pressure usually comes from one of three places: a closed valve, a clogged aerator, or a problem at the meter. Before you call a plumber, check whether the issue is in your whole house or just one fixture. Turn on every tap and shower. If pressure is low everywhere, the problem is likely in your main line or at the meter. If only one or two fixtures are weak, the fix is usually something you can do yourself in minutes.

The fastest win is the aerator — the small screen at the tip of your faucet. Unscrew it by hand and rinse it under running water to clear mineral buildup. Mineral deposits from hard water clog these screens over time. Screw it back on and test the pressure. If that does not work, move to the shut-off valves.

Key Takeaways

  • Check whether low pressure affects your whole house or just one fixture, because the location tells you where the problem is.
  • Clean the aerator screen at the faucet tip first — mineral buildup is the most common cause and takes two minutes to fix.
  • Look for a shut-off valve under the sink or near the water meter and make sure it is fully open, not partially closed.
  • If pressure is low everywhere and valves are open, the problem is in the main line or meter, and you will need to contact your water company or a plumber.

Check the shut-off valves under your sinks

Every sink, toilet, and shower has a shut-off valve nearby — usually under the sink or behind the toilet. These valves control water flow to that fixture. If someone turned one partway closed, pressure to that fixture drops. Look under your sink and find the valve where the water line enters. It should be a small knob or lever. Turn it counterclockwise (or pull the lever outward if it is a ball valve) until it stops. Do not force it.

If the valve was partially closed, pressure should return when ready. If it was already fully open, move on. Check the main shut-off valve near your water meter as well. This valve controls water to your entire house. It is usually in a basement, crawl space, or outside near the meter box. If it is only partially open, that explains low pressure everywhere. Turn it fully open the same way — counterclockwise for a gate valve, or pull outward for a ball valve.

Look for leaks in your main water line

A leak in the main line between the meter and your house reduces pressure throughout the home. Check your water meter reading, then do not use any water for two hours. Check the meter again. If it moved, you have a leak somewhere in the main line. You will not always see water pooling — the leak might be underground or inside a wall.

A main line leak is not something to fix yourself. Contact your water company first. Many water companies will repair leaks on their side of the meter at no charge. If the leak is on your property (between the meter and your house), you will need a licensed plumber. Main line repairs can be expensive, but ignoring a leak wastes water and raises your bill.

Flush your water heater if pressure is low only for hot water

If cold water pressure is normal but hot water pressure is weak, sediment has built up inside your water heater. Minerals in the water settle at the bottom of the tank and narrow the outlet pipe. Flushing the tank removes this buildup and restores pressure.

Turn off the power to your water heater (switch off the breaker for electric, or the gas valve for gas). Attach a garden hose to the drain valve at the bottom of the tank and run it to a floor drain or outside. Open the drain valve and let the tank empty completely. Close the drain valve, remove the hose, turn the power back on, and refill the tank. This usually takes 30 minutes to an hour. If you are not comfortable doing this, a plumber can do it for about $150 to $300.

Check for a pressure regulator that may have failed

Some homes have a pressure regulator — a bell-shaped device on the main water line near the meter. This device keeps pressure from the street from getting too high and damaging your pipes. If the regulator fails, pressure can drop suddenly. You will see it as a brass or plastic dome about the size of a fist, usually with a gauge on top.

If you suspect the regulator has failed, you can test it by turning on an outdoor faucet and checking the pressure with a pressure gauge (available at hardware stores for $10 to $20). Normal household pressure is 40 to 80 pounds per square inch. If the reading is below 40 and your shut-off valves are open, the regulator may be the problem. Replacing a regulator costs $150 to $300 and requires a plumber.

Consider whether your pipes are too old or too small

Galvanized steel pipes, common in homes built before 1980, corrode from the inside over decades. The corrosion narrows the pipe opening and reduces flow. If your home is older and pressure has been dropping gradually over years, corrosion is likely. Replacing galvanized pipes with copper or PEX is expensive — usually $3,000 to $8,000 for a whole house — but it is the only permanent fix.

Undersized pipes can also cause low pressure. If a previous owner added fixtures or extended lines without upgrading pipe diameter, the system cannot deliver enough water. This is less common but happens in older homes that have been heavily renovated. A plumber can diagnose this by checking pipe sizes and water flow rates.

Know when to call a plumber versus your water company

If pressure is low everywhere and your shut-off valves are fully open, the problem is either in the main line (between the meter and your house) or at the meter itself. Call your water company first. They can check the pressure on their side of the meter and tell you whether the problem is theirs or yours. This call is free and takes five minutes.

If the water company confirms pressure is normal at the meter, the problem is in your main line or inside your house. That is when you call a plumber. If pressure is low in only one or two fixtures, you can usually fix it yourself by cleaning aerators or opening valves. A plumber visit for diagnosis and repair typically costs $100 to $200 for the service call, plus the cost of any parts or repairs needed.

Frequently Asked Questions

Why is my water pressure low only in the morning?

Morning pressure dips happen when your water company is flushing the main lines or when demand is highest. This is normal and temporary. If it happens every morning and lasts more than an hour, contact your water company. If it happens only occasionally, it is likely a system-wide issue, not a problem with your home.

Can I increase water pressure by adjusting something myself?

You can restore normal pressure by opening shut-off valves and cleaning aerators. You cannot increase pressure above what the water company delivers. If you want higher pressure for a specific use like a shower, you can install a pressure-boosting pump, which costs $300 to $800 installed. A plumber can assess whether this makes sense for your situation.

What does it mean if water pressure is fine but the flow is weak?

Pressure and flow are different. Pressure is the force behind the water; flow is the amount coming out. Weak flow with normal pressure usually means a clogged aerator or a partially closed valve. Clean the aerator first. If that does not work, check the shut-off valve under the sink to make sure it is fully open.

Is low water pressure a sign of a serious problem?

Low pressure is usually a minor issue — a clogged aerator or a valve that is not fully open. It becomes serious only if it signals a main line leak or corroded pipes. Check for leaks by reading your meter, and ask a plumber to inspect old pipes if pressure has been dropping over months or years.

How much does it cost to fix low water pressure?

Fixes range from free (opening a valve or cleaning an aerator) to $150 to $300 (flushing a water heater or replacing a regulator) to thousands of dollars (replacing corroded main lines). Start with the free checks. If those do not work, a plumber's diagnostic visit costs $100 to $200 and will tell you exactly what needs to be done and what it will cost.