Where the problem usually starts
Low water pressure often comes from one of three places: a closed or partially closed valve, mineral buildup inside pipes or fixtures, or a problem with your municipal water supply. Before you call a plumber, you can check the first two yourself in about ten minutes.
Start by testing whether the problem is everywhere in your house or just one room. Turn on a sink in the kitchen, then one in the bathroom, then a shower. If pressure is low everywhere, the issue is likely in your main water line or at the meter. If it's only in one room, the problem is almost certainly a clogged aerator or a closed valve under that sink.
Key Takeaways
- Check the shut-off valve under your sink or near your water meter—it should be fully open, with the handle parallel to the pipe.
- Unscrew and clean the aerator (the screen at the tip of your faucet) by soaking it in vinegar to dissolve mineral deposits.
- If pressure is low everywhere in the house, the problem may be at your meter or in the main line, and you should contact your water company first.
- Sediment in your water heater can reduce pressure to hot-water fixtures; draining the tank may restore flow.
- If you have old galvanized pipes, mineral buildup inside them may require professional cleaning or replacement.
Opening the shut-off valve all the way
Every sink has a shut-off valve underneath it, usually two of them—one for hot water and one for cold. These are small knobs or levers. If the handle is perpendicular to the pipe (pointing straight out to the side), the valve is closed. If it's parallel to the pipe (pointing along the same direction as the water flows), it's open.
Check both valves under the sink where you have low pressure. If either one is closed or only partially open, turn it counterclockwise until it stops. Do not force it. You should feel it turn easily for several rotations, then stop naturally when it reaches the fully open position.
If the valve is stuck or won't turn, do not keep forcing it—you can break the valve and create a leak. Leave it and move to the next step. If you find a closed valve and open it, test the pressure again before doing anything else. Many low-pressure problems stop here.
Cleaning the aerator on your faucet
The aerator is the small screen at the very tip of your faucet. It mixes air into the water stream and also catches sediment and mineral particles. Over time, these particles build up and restrict flow. Cleaning it takes five minutes and costs nothing.
Unscrew the aerator by turning it counterclockwise by hand. If it is stuck, wrap a cloth around it and use a wrench, but turn gently. Once it is off, you will see a small screen inside. Rinse it under running water and use an old toothbrush to scrub away any white or brown buildup. If the buildup is heavy, soak the aerator in white vinegar for 30 minutes, then scrub again.
Screw the aerator back on by hand, turning clockwise until it is snug. Do not overtighten. Turn on the faucet and test the pressure. If this was the problem, pressure should return to normal when ready.
Draining sediment from your water heater
If pressure is low only at hot-water taps, sediment has likely settled at the bottom of your water heater tank. This sediment restricts the outlet pipe and slows the flow of hot water. Draining the tank removes it.
Turn off the power to your water heater—flip the breaker if it is electric, or turn the gas valve to the pilot position if it is gas. Wait 30 minutes for the water to cool slightly. Attach a garden hose to the drain valve at the bottom of the tank and run the hose to a floor drain or outside. Open the drain valve slowly and let water run until it runs clear, which usually takes 10 to 15 minutes. Close the valve, remove the hose, and turn the power back on.
If you are not comfortable doing this, or if your water heater is in a tight space, a plumber can do it in under an hour. Do not skip this step if sediment is the problem—the buildup will only get worse and can eventually damage the tank.
Checking your water meter and main shut-off
If pressure is low everywhere in your house, the problem may be at your water meter or in the main line between the meter and your house. Your water meter is usually in the basement, crawl space, or outside in a box near the street.
Locate your meter and look for a shut-off valve near it. This valve controls water to your entire house. Make sure the handle is parallel to the pipe and fully open. If it is not, open it the same way you would open a valve under a sink—turn counterclockwise until it stops.
If the main valve is already open and pressure is still low everywhere, contact your water company. Low pressure at the meter usually means a problem in the municipal line or at the treatment plant, and the water company needs to know. They can test the pressure at the meter and tell you whether the problem is on their side or yours.
When mineral buildup is inside the pipes
If your house has galvanized steel pipes (common in homes built before 1980), minerals can build up inside the pipes themselves over decades. This is different from a clogged aerator—the buildup is throughout the line, not just at one fixture. You cannot clean this yourself.
Signs of internal pipe buildup include low pressure everywhere, water that looks slightly discolored or cloudy, and pressure that gets worse gradually over months or years. A plumber can confirm this by testing pressure at different points in your system. If the problem is confirmed, the pipes usually need to be replaced, which is a larger job. Some plumbers offer chemical flushing as a temporary measure, but it is not permanent.
If you suspect this is your problem, get a quote from a licensed plumber. Replacing galvanized pipes with copper or PEX is the lasting solution, though it is an investment. In the meantime, you can install a whole-house water filter to slow future buildup, though it will not restore pressure that is already lost.
When to call a plumber
Call a plumber if you have checked the shut-off valves, cleaned the aerators, and drained the water heater (if applicable) and pressure is still low. Also call if the main shut-off valve is stuck or will not open, or if you suspect buildup inside the pipes themselves.
A plumber can test pressure at different points in your system to pinpoint where the problem is. They can also inspect your pipes for corrosion or damage and recommend whether repair or replacement makes sense. If the problem is at the meter or in the municipal line, they can tell you that too and advise you to contact the water company.
Frequently Asked Questions
Can low water pressure damage my appliances?
Low pressure can strain dishwashers and washing machines because they rely on a minimum flow rate to work properly. Over time, this can shorten their lifespan. If pressure is very low, these appliances may not fill completely or may run longer cycles than normal. Restoring pressure protects them.
Why is my water pressure fine in winter but low in summer?
Summer demand is higher, so municipal water systems sometimes reduce pressure during peak hours to manage supply. This is normal and temporary. If pressure drops only during certain times of day, contact your water company to confirm. If it is low all the time, the problem is in your house.
Will a pressure regulator help if my pressure is too low?
A pressure regulator reduces high pressure, not low pressure. If your pressure is already low, a regulator will make it worse. You need to fix the underlying cause first—a clogged aerator, a closed valve, or sediment in the heater.
Is it safe to use a chemical drain cleaner to unclog a pipe and restore pressure?
No. Drain cleaners are designed to dissolve organic material like hair and soap, not mineral buildup. They can damage pipes and are not effective for pressure problems. Stick to vinegar soaking for aerators, or call a plumber for internal pipe issues.
How often should I clean my water heater to prevent sediment buildup?
Most plumbers recommend draining your water heater once a year, or more often if you have hard water. If you have never drained it and your water heater is more than five years old, drain it now. After that, annual maintenance will keep sediment from building up again.