Where the problem usually starts
Low water pressure in your house usually comes from one of three places: a problem with your water meter or the line from the street, a closed or partially closed valve inside your home, or mineral buildup in your pipes or fixtures. The fastest way to find out which one is yours is to check whether the pressure is low everywhere in the house or only at certain taps.
If pressure is low everywhere, the problem is likely before the main shutoff valve — meaning it is either with your water company or the line they own. If pressure is low only in one room or at one fixture, the problem is in your home's plumbing. Start by checking the main shutoff valve, usually located near the water meter or where the line enters the house. It should be fully open; if it is partially closed, turning it all the way open may solve the problem when ready.
Key Takeaways
- Check your main shutoff valve first — it is often partially closed by accident, and opening it fully takes seconds.
- If pressure is low everywhere in the house, contact your water company; if it is low in one room only, the problem is in your home's pipes.
- Mineral buildup in aerators (the screens on tap spouts) is the most common cause of low pressure at individual fixtures and costs almost nothing to fix.
- A pressure regulator that has failed will cause low pressure throughout the house and usually needs to be replaced by a plumber.
- If your water company confirms normal pressure at the meter but you have low pressure inside, you may have a leak or blockage in your main line.
Cleaning aerators and showerheads
The screen at the end of your tap or showerhead is called an aerator. Mineral deposits from hard water build up on this screen over months or years and restrict flow. This is the most common cause of low pressure at a single fixture, and it is the easiest to fix.
Unscrew the aerator by hand or with a wrench if it is stuck. Soak it in white vinegar for one to two hours, then scrub the screen with an old toothbrush to remove the mineral crust. Rinse it thoroughly and screw it back on. If the screen is too damaged to clean, you can buy a replacement aerator at any hardware store for a few dollars. For showerheads, the same process works — unscrew it, soak it, scrub it, and reinstall it.
If cleaning the aerator does not restore pressure, the problem is in the line behind it, not at the fixture itself.
Checking for leaks in your main line
A leak in the main water line between the meter and your house will lower pressure throughout the home. To check for a leak, turn off all water use inside the house — no running taps, no toilets flushing, no washing machines. Then look at your water meter. If the dial is moving even though no water is running, you have a leak.
If you find a leak, you will need to call a plumber. Leaks in the main line are usually underground and require excavation to repair. Before you call, contact your water company and ask them to confirm the pressure at the meter on their side. If they confirm normal pressure there, the leak is definitely in your line and is your responsibility to fix.
If the meter is not moving and pressure is still low everywhere, the problem is either with the water company's line or with a failed pressure regulator inside your home.
Testing and replacing the pressure regulator
Many homes have a pressure regulator — a bell-shaped device usually located on the main water line just after the meter. This device reduces water pressure from the street (which can be 60 to 80 pounds per square inch) to a safer level for your home's pipes (usually 40 to 60 psi). If this regulator fails, pressure drops throughout the house.
You can buy an inexpensive pressure gauge at a hardware store and screw it onto an outdoor hose bib to measure your water pressure. Normal household pressure is between 40 and 60 psi. If your reading is below 40 psi and you have confirmed that the main shutoff valve is fully open, the regulator may have failed.
Replacing a pressure regulator is a job for a plumber. The cost varies by region and the type of regulator, but it is usually between $300 and $500 including labor. If you do not have a regulator and pressure is still low, contact your water company to check the pressure at the meter.
Flushing sediment from your pipes
Sediment and mineral deposits can build up inside your pipes over time, especially in older homes or areas with hard water. This buildup narrows the pipe and reduces flow. If you have low pressure throughout the house and the main shutoff valve is open, flushing the system may help.
Turn off your water heater and locate the drain valve at the bottom of the tank (or the lowest point in your plumbing system). Attach a garden hose and run water through it into a bucket or drain until the water runs clear. This process can take 15 to 30 minutes. Turn the water heater back on once you are done.
If flushing does not improve pressure, the buildup is likely inside the main line itself, which is harder to address. A plumber can use a hydro-jetting service to blast sediment out of the pipes, though this is expensive and is usually only done if pressure is severely low.
When to contact your water company
Contact your water company if pressure is low everywhere in the house and you have ruled out problems inside your home. Tell them you have checked the main shutoff valve and confirmed it is fully open. Ask them to measure the pressure at the meter on their side of the line. If they confirm normal pressure there, the problem is in your home's plumbing. If they confirm low pressure at the meter, the problem is with their line or system, and they are responsible for fixing it.
Some water companies will send someone to check the meter for free. Others may charge a small fee. Ask about this when you call. Keep a record of the date and time you called and the name of the person you spoke with, in case you need to follow up.
When to call a plumber
Call a plumber if you have low pressure throughout the house and you have confirmed that the main shutoff valve is fully open and the water company has confirmed normal pressure at the meter. A plumber can test your pressure regulator, check for leaks in the main line, and identify blockages inside your pipes. They can also perform hydro-jetting if sediment buildup is severe.
Before you call, have the following information ready: whether pressure is low everywhere or only in certain rooms, what your water pressure reading is (if you measured it), and whether you have noticed any wet spots in your yard or unusually high water bills. This information will help the plumber diagnose the problem faster.
Frequently Asked Questions
Why is my water pressure low only in the kitchen but normal everywhere else?
The problem is almost certainly in the aerator on your kitchen tap. Unscrew it, soak it in vinegar for an hour, scrub it with a toothbrush, and reinstall it. If that does not work, the shutoff valve under the sink may be partially closed — check that it is fully open by turning the handle until it stops.
Can I fix low water pressure myself or do I need a plumber?
You can clean aerators, check the main shutoff valve, and measure pressure with a gauge yourself. If the problem is a failed pressure regulator, a leak in the main line, or sediment buildup inside the pipes, you will need a plumber. Most plumbers charge $100 to $200 for a service call to diagnose the problem.
What is normal water pressure for a house?
Normal household water pressure is between 40 and 60 pounds per square inch (psi). Anything below 40 psi is considered low. You can measure your pressure with an inexpensive gauge from a hardware store — screw it onto an outdoor hose bib and turn the water on.
Does hard water cause low pressure?
Hard water does not cause low pressure directly, but the mineral deposits it leaves behind can build up on aerators and inside pipes over time. Cleaning aerators is a quick fix. If buildup is inside the pipes, a plumber may need to flush or hydro-jet the system.
How much does it cost to fix low water pressure?
Cleaning an aerator costs nothing. A plumber's service call to diagnose the problem usually costs $100 to $200. Replacing a pressure regulator costs $300 to $500. Hydro-jetting to remove sediment costs $400 to $800. A leak repair depends on where the leak is and how deep it is buried.