Where the Problem Usually Starts
Low water pressure in your home usually comes from one of three places: the main shutoff valve is partly closed, sediment is blocking your aerators or showerheads, or your water meter valve is not fully open. Start by checking these three things before you call a plumber, because fixing any of them takes 10 minutes and costs nothing.
The main shutoff valve is typically located where the water line enters your house—often in the basement, crawl space, or under the kitchen sink. It looks like a handle or a round knob. If someone turned it partway closed, even slightly, it will cut your pressure throughout the whole house. Turn it all the way counterclockwise (for a handle) or fully left (for a knob) until it stops. Do the same with your water meter valve if you can access it—it is usually in a box in your front yard or on the street side of your property.
Key Takeaways
- Check your main shutoff valve and water meter valve first—both should be turned fully open, and a partially closed valve is the most common cause of low pressure throughout your whole house.
- Clean the aerators on your faucets and the screens in your showerheads by unscrewing them, rinsing out sediment, and soaking them in vinegar for an hour if mineral buildup is heavy.
- If pressure is low in only one room or one fixture, the problem is local to that line and usually fixable by cleaning or replacing the aerator.
- Pressure regulators wear out over time and can fail closed, restricting flow to the entire house—replacing one takes an hour and costs $50 to $150 in parts.
- If all three quick fixes fail and pressure is still low everywhere, you may have a leak in your main line or a problem at the water company's meter, and you will need a plumber to diagnose it.
Cleaning Aerators and Showerhead Screens
Sediment and mineral buildup inside aerators (the screens at the end of faucet spouts) and showerhead screens are the second most common cause of low pressure. You can clean these yourself in about 15 minutes per fixture. Unscrew the aerator or showerhead by hand—most turn counterclockwise—and hold it up to the light. If you see white, tan, or rust-colored deposits, that is the problem.
Rinse the aerator under running water and use an old toothbrush to scrub away loose sediment. If buildup is heavy, soak the aerator in white vinegar for one to two hours, then scrub again and rinse thoroughly. Reassemble it and test the pressure. If the screen is damaged or has holes, replace it with a new one—aerators cost $2 to $8 at any hardware store and take 30 seconds to install.
If pressure improves at that one fixture but remains low everywhere else, you have found a local problem and can stop here. If pressure is still low throughout the house after cleaning all aerators and showerheads, move to the next step.
Testing Pressure at Different Fixtures
Before you spend money on repairs, figure out whether the problem is everywhere or just in one area. Turn on a cold-water faucet in your kitchen, then check a bathroom faucet, then a shower. If pressure is weak at all of them, the problem is in your main line or your pressure regulator. If pressure is normal in the kitchen but weak in the bathroom, the problem is in the line running to that bathroom.
Also test both hot and cold water. If only hot water is weak, the problem is in your hot water heater or the line feeding it, not your main supply. If only cold water is weak, the problem is in your cold-water line. This information will save a plumber time and save you money on the diagnosis.
Checking and Replacing Your Pressure Regulator
A pressure regulator is a bell-shaped or cylindrical device screwed onto the main water line, usually near where the water enters your house. It keeps pressure from getting too high and damaging your pipes and fixtures. Over time, the internal valve can fail and restrict flow, making pressure low everywhere in the house.
If your regulator has a gauge on it, you can read the pressure directly. Normal household water pressure is 40 to 80 pounds per square inch (psi). If the gauge reads below 40 psi and your shutoff valve is fully open, the regulator may be failing. You can try adjusting it by turning the adjustment screw on top counterclockwise to increase pressure, but if that does not work, the regulator needs replacement.
Replacing a regulator takes about an hour if you are comfortable with basic plumbing. Turn off the main shutoff valve, unscrew the old regulator with a wrench, wrap the threads of the new one with plumber's tape, and screw it on hand-tight, then snug it with a wrench. A new regulator costs $50 to $150. If you are not comfortable doing this, a plumber can replace it in 30 to 45 minutes for $150 to $300 in labor.
When You Have Pressure in Some Rooms but Not Others
If pressure is normal in your kitchen but weak in your upstairs bathroom, the problem is in the line running to that bathroom, not your main supply. Start by cleaning the aerators and showerhead screens in that room—sediment buildup is the most common cause. If that does not fix it, there may be a partially closed shutoff valve under the sink or behind the toilet that someone turned down.
Look for a small valve on the water line under the sink or in the wall behind the toilet. It should be a small handle or knob. Turn it fully counterclockwise or fully left. If the valve is stuck or will not turn, do not force it—call a plumber, because forcing it can break it and leave you unable to shut off water to that fixture.
If the valve is already fully open and cleaning the aerators did not help, there may be a blockage or corrosion inside that section of pipe. This requires a plumber to diagnose and fix.
Leaks and Water Meter Problems
If your main shutoff valve is fully open, your pressure regulator is working, and your aerators are clean, but pressure is still low everywhere, you may have a leak in your main water line between the meter and your house. A leak will also show up as higher than normal water bills.
Check your water meter to see if it is running when no water is running in your house. Turn off all faucets and fixtures, wait 10 minutes, then look at the meter dial. If it is still moving, you have a leak. Mark the meter reading, wait an hour without using any water, and check it again. If it has changed, you have a leak somewhere in your main line, and you will need a plumber to locate and repair it.
It is also possible that the problem is on the water company's side of the meter. Call your water company and report low pressure. They can check their main line and the meter itself at no cost to you. If the problem is on their side, they will fix it.
When to Call a Plumber
Call a plumber if you have checked your shutoff valve, cleaned your aerators, tested your pressure regulator, and pressure is still low everywhere. Also call if pressure is low in one room and the shutoff valve for that room is stuck or will not turn, or if you suspect a leak in your main line. A plumber can use a pressure gauge to measure your exact pressure, locate leaks with specialized equipment, and replace pipes or regulators if needed.
Before the plumber arrives, write down which fixtures have low pressure, whether it is hot water, cold water, or both, and what your water bills have looked like recently. This information will help them diagnose the problem faster.
Frequently Asked Questions
How do I know if my water pressure is actually low?
Normal household water pressure is 40 to 80 psi. If you have a pressure gauge, you can measure it directly by screwing the gauge onto an outdoor faucet. If you do not have a gauge, low pressure usually feels like a weak stream from faucets and showerheads that takes a long time to fill a bucket or glass. If you are used to a strong shower and it suddenly feels weak, that is a sign.
Can low water pressure damage my pipes?
Low pressure itself does not damage pipes, but the cause of low pressure sometimes does. A leak in your main line will waste water and can erode soil around your foundation. Sediment buildup that causes low pressure can also cause damage over time if it builds up inside your pipes. That is why it is worth fixing.
Is low water pressure dangerous?
Low pressure is not a health hazard by itself, but it can make it harder to clean dishes and shower properly. If your pressure drops suddenly, it could signal a leak or a problem at the water company, so it is worth investigating.
What is the difference between a shutoff valve and a pressure regulator?
A shutoff valve straightforward turns water on and off—it does not control pressure. A pressure regulator controls how much pressure the water has as it enters your house. You need both. The shutoff valve lets you stop water flow for repairs, and the regulator protects your pipes from damage caused by pressure that is too high.
Can I increase water pressure by adjusting my pressure regulator myself?
Yes, if your regulator has an adjustment screw on top. Turn it counterclockwise to increase pressure, but do not exceed 80 psi or you risk damaging your pipes and fixtures. If you do not have a pressure gauge, turn it slowly and test the pressure at a faucet after each small adjustment. If adjusting the screw does not work, the regulator is failing and needs replacement.