Where low water pressure usually comes from
Low water pressure in your house usually means one of three things: the problem is between the street and your meter, the problem is inside your home's pipes, or your pressure regulator is set too low. You can narrow this down in minutes by checking whether the problem is everywhere in the house or just at certain fixtures.
If only one faucet or shower has weak pressure, the blockage is downstream of that point—often a clogged aerator or mineral buildup inside that fixture. If the whole house has low pressure, the issue is either in your main line, your pressure regulator, or your water meter. Start by calling your water company's non-emergency line and asking whether they are doing work on your street or whether pressure is low on their side of the meter. If they say pressure is normal, the problem is yours to fix.
Key Takeaways
- Low pressure at one fixture usually means a clogged aerator or mineral deposits inside that faucet, which you can clean yourself in ten minutes.
- Low pressure everywhere in the house points to a problem in your main line, a closed shut-off valve, or a pressure regulator set below 40 PSI.
- Your water company can tell you in one call whether the low pressure is on their side of the meter or yours.
- A pressure regulator costs $50 to $150 and takes a plumber one hour to replace if adjustment does not work.
- Mineral buildup in pipes is permanent without replacing the affected section, so prevention through a water softener is more practical than cure.
Cleaning a clogged aerator at a single faucet
The aerator is the small screen at the tip of your faucet. It mixes air into the water stream and catches sediment. Over time, mineral deposits and debris clog it, and pressure drops at that one faucet while everywhere else in the house is fine.
Unscrew the aerator by hand—most turn counterclockwise—or use a wrench if it is stuck. Rinse it under running water and use an old toothbrush to scrub away white or brown deposits. If deposits are heavy, soak the aerator in white vinegar for 30 minutes, then scrub again. Screw it back on and test the pressure. This fixes the problem in most cases where only one faucet is weak.
If the aerator is clean but pressure is still low at that faucet, the problem is inside the faucet body itself or in the supply line feeding it. A plumber can replace the faucet or the line, but this is usually worth doing only if the faucet is old or the line is corroded.
Checking and adjusting your pressure regulator
A pressure regulator is a bell-shaped valve usually found where the main water line enters your house, often in the basement or crawlspace near the water meter. It keeps pressure from the street from spiking and damaging your pipes. If it is set too low or has failed, your whole house will have weak pressure.
Look for a valve with a screw on top and a gauge attached or nearby. If there is a gauge, read the number—it should be between 40 and 80 PSI (pounds per square inch). If it reads below 40, the regulator may be the problem. If there is no gauge, you can buy a water pressure gauge at any hardware store for $10 to $20, screw it onto an outdoor faucet, and turn the faucet on to read your pressure.
If pressure is below 40 PSI, try turning the adjustment screw on top of the regulator clockwise a quarter turn, then test pressure again at a faucet. Turn it slowly—a quarter turn at a time—until pressure reaches 50 to 60 PSI. Do not exceed 80 PSI, as high pressure damages pipes and appliances. If adjusting the screw does not raise pressure, the regulator has failed internally and needs replacement.
Finding and opening a closed shut-off valve
Between the street and your house is a shut-off valve that lets you stop water flow in an emergency. If this valve is partially closed, pressure drops everywhere in the house. Check whether it is fully open by locating it—usually in the basement, crawlspace, or outside near the meter—and looking at the handle.
The handle should be parallel to the pipe (pointing the same direction the water flows). If it is perpendicular to the pipe (at a right angle), the valve is closed or partially closed. Turn it parallel to the pipe by hand. If it is stuck, do not force it—call a plumber. Once it is fully open, test pressure at a faucet. This is a quick fix that solves the problem in some cases.
When mineral buildup is blocking your pipes
Hard water leaves mineral deposits inside pipes over years. In severe cases, these deposits narrow the pipe opening enough to reduce pressure throughout the house. This is permanent—you cannot flush out mineral buildup—so the only real fix is replacing the affected pipe section.
If you have hard water (white or orange deposits on faucets, soap that does not lather, stiff laundry), mineral buildup may be the cause of low pressure. A plumber can confirm this by checking pressure at different points in your house. If pressure is normal at the meter but drops significantly by the time water reaches your faucets, mineral deposits are likely the culprit.
Replacing corroded pipes is expensive and disruptive. A more practical approach is installing a water softener, which removes minerals before they enter your pipes. This prevents future buildup and is cheaper than replacing pipes later. Water softeners range from $500 to $2,500 installed, depending on your water hardness and household size.
When to call a plumber
Call a plumber if pressure is low everywhere in the house and you have already confirmed that your water company's pressure is normal, your shut-off valve is fully open, and your pressure regulator is set above 40 PSI. A plumber can test pressure at multiple points to pinpoint whether the problem is in your main line, a hidden leak, or internal pipe corrosion.
Also call a plumber if you suspect a leak. Low pressure sometimes signals a crack in your main line that is leaking water into the ground. Signs include wet spots in your yard, unusually high water bills, or soft ground near your foundation. A plumber can locate the leak using a listening device and either repair it or recommend replacement.
If your pressure regulator needs adjustment and you are not comfortable working with it, a plumber can do this in 15 minutes for a service call fee. If the regulator has failed, replacement takes about an hour and costs $200 to $400 total (parts and labor vary by region and plumber).
Preventing low pressure before it starts
Maintain your aerators by cleaning them once a year if you have hard water, or every few years if your water is soft. This takes ten minutes and prevents most single-faucet pressure problems.
If you have hard water, consider a water softener to prevent mineral buildup in your pipes. This also extends the life of water heaters, washing machines, and dishwashers. A whole-house softener is the most effective option, though point-of-use filters (installed under a single sink) work for that fixture only.
Check your pressure regulator every few years by reading the gauge or using a pressure gauge on an outdoor faucet. If pressure creeps above 80 PSI, adjust the regulator down. High pressure is harder on pipes and fixtures than low pressure and causes leaks over time.
Frequently Asked Questions
Can low water pressure damage my pipes or appliances?
Low pressure itself does not damage pipes. High pressure does—above 80 PSI puts stress on joints and seals. Low pressure is uncomfortable but safe. However, if low pressure is caused by a leak in your main line, the leak itself can erode soil and eventually cause the pipe to fail.
Why is my water pressure low only in the morning?
Morning low pressure usually means your water company is running a hydrant test or doing maintenance on your street. Call them to confirm. If they say their pressure is normal, the problem is likely a pressure regulator that is failing—it may work fine once water has been running for a while, then fail again after sitting overnight.
How do I know if my pressure regulator has failed?
A failed regulator usually shows low pressure that does not improve when you adjust the screw, or pressure that keeps rising even after you turn the adjustment screw down. Some regulators fail silently and just need replacement. A plumber can test it with a gauge to confirm.
Is a water softener worth it if I only have low pressure in one room?
No. If only one faucet or shower has low pressure, the problem is that fixture's aerator or supply line, not your whole-house water hardness. Clean the aerator first. A water softener makes sense only if you have hard water throughout the house and want to prevent mineral buildup in your pipes.
Can I increase water pressure by adjusting something at the meter?
No. The meter itself does not control pressure—it only measures flow. The pressure regulator, which is usually near the meter, does control pressure. You can adjust the regulator, but not the meter. If you are unsure which valve is which, take a photo and show it to a plumber before touching anything.