What causes low water pressure and how to fix it
Low water pressure usually comes from one of three places: a problem at the meter or main line (which you cannot fix), a clogged or partially closed valve in your house (which you can), or sediment buildup in your aerators and showerheads (which takes ten minutes to clean). Start by checking whether the problem is everywhere in the house or only at one fixture. If it is only one sink or shower, the fix is almost always to unscrew the aerator or showerhead, soak it in vinegar for an hour, and scrub out the mineral deposits. If pressure is low throughout the house, move to the main water shut-off valve and the pressure regulator.
Before you call a plumber, you can rule out the most common causes yourself. The whole process takes less than an hour and costs nothing if you already have vinegar and a wrench at home.
Key Takeaways
- Low pressure at a single faucet or showerhead is almost always mineral buildup in the aerator, which you can clean by soaking it in vinegar and scrubbing it with an old toothbrush.
- Low pressure everywhere in the house points to a partially closed shut-off valve or a faulty pressure regulator, both located near your water meter.
- The main water shut-off valve has a handle that should point along the pipe when fully open; if it is perpendicular to the pipe, it is partially closed.
- If you have a pressure regulator (a bell-shaped fitting near the meter), you can adjust it with a wrench, but if it is broken, a plumber will need to replace it.
- Water pressure above 80 pounds per square inch can damage pipes and appliances, so do not increase pressure beyond what you need.
Clean aerators and showerheads first
An aerator is the small screen at the tip of your faucet. Over time, minerals from your water build up on it and restrict flow. This is the most common cause of low pressure at a single fixture, and it takes minutes to fix.
Unscrew the aerator by hand or with a wrench if it is stuck. Soak it in white vinegar for 30 minutes to an hour. Use an old toothbrush or a soft brush to scrub away the white or tan mineral deposits. Rinse it thoroughly under running water and screw it back on. Do the same for any showerhead that has low pressure. If you have a handheld showerhead, soak the entire head, not just the face.
If the aerator is badly corroded or has a hole in the screen, replace it. Aerators cost two to five dollars and screw on by hand. Bring the old one to a hardware store to match the thread size, or take a photo of the faucet and ask the staff.
Check the main shut-off valve
The main water shut-off valve controls water flow into your entire house. It is usually located in the basement, crawlspace, or utility room near where the water line enters the building. Look for a valve with a handle on the water line coming from the meter.
The handle should point in the same direction as the pipe when the valve is fully open. If the handle is perpendicular to the pipe (pointing sideways), the valve is partially closed. Turn the handle so it lines up with the pipe. This is a straightforward quarter-turn, and you should feel it move smoothly. Do not force it.
If the handle is already aligned with the pipe and you still have low pressure everywhere, the valve itself may be stuck or corroded inside. This is a job for a plumber, because forcing a stuck valve can break it and leave you unable to shut off water in an emergency.
Inspect and adjust the pressure regulator
Not all homes have a pressure regulator, but if yours does, it will be a bell-shaped or cylindrical fitting on the main water line, usually near the meter or shut-off valve. Its job is to reduce water pressure from the street (which can be 100 pounds per square inch or higher) to a safer level for your home (usually 50 to 80 pounds per square inch).
If your pressure regulator is faulty, it can cause pressure to drop too low or fluctuate. You can test this with an inexpensive pressure gauge, which screws onto an outdoor faucet or a washing machine outlet. Normal household pressure is 50 to 80 pounds per square inch. If your gauge reads below 40, the regulator may be the problem.
Some regulators have an adjustment screw on top. You can try turning it clockwise a quarter-turn to increase pressure, then test again with the gauge. If that does not help, or if the regulator is leaking, it needs to be replaced by a plumber. Replacement usually costs between 150 and 300 dollars, depending on your region and the regulator model.
Look for leaks in visible pipes
A leak in the main water line between the meter and your house can reduce pressure throughout the home. Walk around your basement, crawlspace, or the area where the water line enters, looking for wet spots, drips, or mineral stains on pipes.
Small leaks may not be obvious. If you see white or rust-colored mineral deposits on a pipe, water has been seeping there. A pinhole leak can look like a tiny wet spot or a small white crusty area. If you find a leak, mark it and call a plumber. Do not try to patch it yourself—the pressure inside the line is too high, and a temporary fix can fail suddenly.
If you do not see any visible leaks and pressure is still low everywhere, the problem is likely inside the meter or in the line between the meter and the street. This is the water company's responsibility, and you should contact them to report low pressure.
Know when to call a plumber
Call a plumber if you have tried cleaning aerators and checking the shut-off valve and pressure is still low, or if you find a leak in a visible pipe. You should also call if the shut-off valve is stuck or if you suspect the pressure regulator is broken.
A plumber can use a pressure gauge to measure your water pressure accurately, identify which part of the system is failing, and replace regulators, valves, or damaged pipe sections. In most areas, a service call costs 100 to 200 dollars, and repairs beyond that depend on what needs to be replaced.
If low pressure is only at one or two fixtures and cleaning the aerators did not help, the problem may be inside the faucet itself. A plumber can rebuild or replace the faucet cartridge, which usually costs 150 to 300 dollars total.
Do not increase pressure beyond 80 pounds per square inch
Water pressure that is too high can damage pipes, water heaters, and appliances like washing machines and dishwashers. If your pressure is above 80 pounds per square inch, you should have a pressure regulator installed or adjusted to bring it down, not up.
High pressure causes leaks to develop faster, reduces the lifespan of fixtures, and can create a hammering sound in the pipes when you turn off a faucet quickly. If you have adjusted a pressure regulator and now your pressure is too high, turn the adjustment screw counterclockwise a quarter-turn and test again.
Frequently Asked Questions
Can I increase water pressure by adjusting the pressure regulator myself?
Yes, if you have a pressure regulator with an adjustment screw. Turn it clockwise a quarter-turn, wait a few minutes for the system to stabilize, then test with a pressure gauge. If pressure is still low, turn it another quarter-turn. Stop if you reach 80 pounds per square inch, because higher pressure damages pipes and appliances.
What is a normal water pressure reading?
Household water pressure should be between 50 and 80 pounds per square inch. Below 40 is too low and will cause weak flow. Above 80 can damage pipes and fixtures. You can measure it with an inexpensive pressure gauge that screws onto an outdoor faucet or washing machine outlet.
Why is my water pressure low only in the morning?
Morning low pressure often happens because the water company is doing maintenance or because demand in your neighborhood is very high. It usually returns to normal within an hour. If it happens every morning, contact your water company to ask if they are doing scheduled work. If not, the problem may be in your pressure regulator or a slow leak.
Do I need a pressure regulator?
Most homes have one, but not all. If your water comes from a well, you probably do not have a regulator. If your water comes from the city, check near your meter for a bell-shaped or cylindrical fitting. If you do not have one and your pressure is above 80 pounds per square inch, a plumber can install one to protect your pipes and appliances.
How much does it cost to fix low water pressure?
Cleaning aerators is free. A plumber's service call is usually 100 to 200 dollars. If the pressure regulator needs to be replaced, add 150 to 300 dollars. If a pipe is leaking or a valve is stuck, costs vary depending on the repair needed and your location.