Start with the water meter shut-off valve and pressure gauge
Low water pressure usually comes from one of three places: a partially closed valve you can open yourself, sediment clogging your aerators and screens, or a pressure regulator that has failed. Before you call a plumber, check your main water shut-off valve—the one near your water meter, typically in the basement, crawlspace, or outside in a box. It should be fully open. If it is only partway open, turn the handle counterclockwise until it stops. This single step fixes the problem in roughly one out of every five homes with low pressure complaints.
Next, buy an inexpensive water pressure gauge (under $15 at any hardware store) and screw it onto an outdoor faucet or a hose bib. Turn on the water and read the pressure. Normal household pressure is between 40 and 80 pounds per square inch (psi). If your reading is below 40 psi, you have a real pressure problem. If it is above 80 psi, you may actually have too much pressure, which can damage fixtures and appliances—in that case, you need a pressure regulator installed, not a pressure boost.
Key Takeaways
- Check your main shut-off valve first—it may be partially closed and is the fastest fix if it is.
- A water pressure gauge costs under $15 and tells you whether your pressure is genuinely low (below 40 psi) or normal.
- Sediment in aerators and screens is the most common cause of low pressure in a single faucet or shower head.
- If pressure is low throughout the house, the problem is usually your pressure regulator, which a plumber must replace.
- Mineral buildup in old pipes can reduce pressure over time, but replacing pipes is expensive and usually only necessary in homes over 50 years old.
Clean aerators and screens on faucets and shower heads
If only one faucet or shower head has low pressure, the problem is almost always sediment trapped in the aerator (the screen at the faucet tip) or in the shut-off valve under the sink. Start by unscrewing the aerator from the faucet tip—turn it counterclockwise by hand or with a wrench if it is stuck. Rinse it under running water and use an old toothbrush to scrub away any white or brown buildup. If the screen is heavily clogged, soak it in white vinegar for 30 minutes, then scrub again.
Screw the aerator back on and test the pressure. If it is still low, the problem is likely in the shut-off valve under the sink. Turn off the water at that valve (the small knob on the pipe under the sink), then unscrew the supply line—the flexible hose that feeds water into the faucet. Turn the water back on briefly into a bucket to flush out sediment, then turn it off again and reattach the line. This clears trapped particles without requiring you to take apart the valve itself.
Check for leaks that reduce pressure throughout the house
A hidden leak in your supply line can lower pressure everywhere in the home, not just at one faucet. The easiest way to spot a leak is to turn off all the water in your house—close every faucet, toilet, and appliance—then look at your water meter. If the meter is still moving, water is leaking somewhere in your pipes.
Check your water bill for a sudden jump, which often signals a leak. Look for wet spots in your basement, crawlspace, or yard, or listen for running water when nothing is turned on. If you find a leak, you will need a plumber to locate and repair it. A leak in the main supply line is not something a homeowner can fix alone, and ignoring it will waste water and keep your pressure low.
Replace a failed pressure regulator
If your pressure gauge shows low pressure throughout the house, and your shut-off valve is fully open, the problem is almost certainly your pressure regulator. This is a bell-shaped device usually located on the main water line where it enters your home, often near the shut-off valve. A regulator that has failed internally will not maintain proper pressure, and it cannot be repaired—it must be replaced.
Replacing a regulator is a job for a licensed plumber because it requires turning off the main water supply, draining the line, and installing a new regulator with the correct pressure setting (usually 50 to 60 psi). The part itself costs $50 to $150, and labor typically runs $150 to $300 depending on your location and how straightforward the regulator is to access. This is not a DIY repair.
Flush sediment from your water heater
If you have low pressure only when you use hot water, sediment has built up inside your water heater tank. Over time, minerals in the water settle at the bottom and reduce the space available for hot water to flow. Flushing the heater can restore pressure and also extend the life of the tank.
Turn off the power to your water heater (switch off the breaker if it is electric, or turn the gas valve to "pilot" if it is 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—this takes 30 minutes to an hour. Close the drain valve, remove the hose, turn the water supply back on, and let the tank refill. Turn the power back on. If you are not comfortable doing this, a plumber can flush the heater for $100 to $200.
Consider water line replacement for very old homes
Homes built before 1970 sometimes have galvanized steel water pipes that corrode and narrow over decades, reducing pressure throughout the house. If your home is over 50 years old, your pressure has always been low, and you have ruled out every other cause, corroded pipes may be the problem. You can confirm this by having a plumber run a camera through a section of pipe or by having the water tested for iron content.
Replacing all the water lines in a house is expensive—typically $3,000 to $10,000 depending on the size of the home and how accessible the pipes are. This is usually only worth doing if you are already remodeling or if the corrosion is severe enough to affect water quality. If pressure is only slightly low and you can live with it, replacement may not be necessary.
Install a whole-house water pressure booster if pressure is naturally low
If your water company delivers pressure below 40 psi to your home—which happens in some rural areas or at the end of long supply lines—and you have ruled out all other causes, a pressure booster pump can help. This is a tank and pump system that stores water and maintains higher pressure throughout your home. A booster system costs $1,500 to $3,000 installed and requires a plumber to set up.
Before investing in a booster, call your water company and ask what pressure they deliver to your meter. If it is naturally low, a booster is a reasonable solution. If your meter pressure is normal but your home pressure is low, the problem is in your pipes or regulator, and a booster will not fix it.
Frequently Asked Questions
Why is my water pressure low in only one bathroom?
The aerator on that faucet or shower head is almost certainly clogged with sediment. Unscrew the aerator, rinse it, and scrub it with a toothbrush. If the shower head is the problem, you can also soak the entire head in white vinegar for an hour, then scrub and rinse. This fixes the issue in most cases.
Can I increase water pressure by adjusting my pressure regulator myself?
You should not adjust a regulator without knowing what you are doing—turning the adjustment screw the wrong way can damage the regulator or create dangerously high pressure. If your pressure is too low and the regulator is working correctly, the regulator itself may have failed and needs replacement by a plumber.
How do I know if I have a water leak?
Turn off all water in the house, then check your water meter. If the meter is still moving, you have a leak. You can also look for wet spots in your basement, crawlspace, or yard, or listen for running water when nothing is turned on. A sudden spike in your water bill is another sign.
Does low water pressure damage my appliances?
Low pressure can slow down dishwashers and washing machines, but it does not usually damage them. High pressure above 80 psi is more damaging—it can wear out seals and valves over time. If your pressure is above 80 psi, you need a pressure regulator to protect your appliances.
How much does it cost to fix low water pressure?
Cleaning an aerator is free. Flushing a water heater costs $100 to $200 if a plumber does it. Replacing a pressure regulator costs $150 to $300 in labor plus $50 to $150 for the part. Replacing water lines is the most expensive option at $3,000 to $10,000. Start with the free and cheap fixes first.