Start by checking what's actually causing low pressure
Low water pressure usually comes from one of three places: your water meter valve is partially closed, your pressure regulator is set too low, or you have a leak somewhere in your supply line. Before you buy anything or call a plumber, spend ten minutes checking these three things. You'll either fix the problem yourself or give a professional the real information they need.
The water meter valve is a ball valve (shaped like a lever) or a gate valve (shaped like a wheel) located where the main water line enters your house, usually in the basement, crawlspace, or outside near the street. Make sure it's fully open. A ball valve should point in line with the pipe; a gate valve should turn counterclockwise until it stops. If someone partially closed it, opening it fully might solve your pressure problem when ready.
Next, locate your pressure regulator—a bell-shaped or cylindrical device screwed onto the main water line, usually within three feet of where water enters the house. If you have one and the pressure is low everywhere in the house, the regulator may be set too low or may have failed. This is the most common cause of whole-house low pressure.
Key Takeaways
- Check that your water meter valve is fully open and your pressure regulator is set to 50–80 psi before assuming you need repairs.
- A pressure regulator that is set too low or has failed is the most common cause of low pressure throughout the entire house.
- Low pressure in only one room usually means a clogged aerator, mineral buildup in the line, or a leak between that room and the main line.
- You can adjust a pressure regulator yourself by turning the adjustment screw, but if pressure won't hold or keeps dropping, the regulator needs replacement.
- If pressure is normal at the meter but low inside the house, you likely have a leak in your supply line that a plumber will need to locate.
Adjust your pressure regulator if you have one
A pressure regulator keeps water pressure from getting too high and damaging your pipes and fixtures. Normal household water pressure is 50 to 80 pounds per square inch (psi). If your regulator is set below 50 psi, you'll feel weak pressure everywhere. If it's set above 80 psi, you risk leaks and damage.
To adjust the regulator, locate the adjustment screw on top of the bell or cylinder. You'll need a pressure gauge (available at any hardware store for $10–$20) to know what pressure you're actually working with. Screw the gauge onto an outdoor faucet or a hose bib, turn on the water, and read the pressure. If it's below 50 psi, turn the adjustment screw clockwise (usually a quarter turn at a time) to raise pressure. Wait a minute between adjustments and check the gauge again. Stop when you reach 60–70 psi.
If the pressure won't hold steady or keeps dropping back down after you adjust it, the regulator's internal diaphragm has failed and the whole unit needs replacement. This is a job for a plumber—the regulator screws off the main line, but you need to know how to depressurize the system and install the new one correctly.
Replace the regulator if adjustment doesn't work
A failed pressure regulator cannot be repaired—it must be replaced. Signs of failure include pressure that won't stay where you set it, pressure that climbs slowly over hours, or a regulator that leaks water from the adjustment screw. You can buy a replacement regulator at any hardware or plumbing supply store for $30–$100 depending on the brand and size.
Replacing it yourself is possible if you're comfortable working with plumbing connections, but most homeowners call a plumber for this job. The plumber will shut off the main water valve, depressurize the line, unscrew the old regulator, wrap the threads with plumber's tape, screw on the new one, and test the pressure. The whole job usually takes 30 minutes to an hour and costs $150–$300 in labor.
After replacement, use your pressure gauge to set the new regulator to 60–70 psi. Check the pressure again after a few days to make sure it's holding steady.
Fix low pressure in a single room or fixture
If only one sink, shower, or faucet has weak pressure, the problem is local to that fixture or the line feeding it. Start by unscrewing the aerator—the small screen at the tip of the faucet—and rinsing it under hot water. Mineral deposits from hard water often clog aerators and are straightforward to clear. Screw it back on and test the pressure.
If pressure is still weak, the supply line to that fixture may have mineral buildup inside it. For a sink, you can disconnect the supply line under the cabinet and run water into a bucket to see if pressure improves. If it does, the line is clogged and needs to be flushed or replaced. For a shower, this is harder to diagnose without opening walls, so call a plumber if the aerator cleaning didn't work.
Low pressure in only one room—say, the upstairs bathroom—sometimes means a leak in the supply line running to that room. You'll usually notice this as wet spots in walls, ceilings, or crawlspaces, or as a spike in your water bill. A plumber can use a leak detection tool to find where the line is damaged and repair or replace the section.
Check for leaks in your main supply line
If pressure is normal at your water meter but low inside the house, you have a leak somewhere between the meter and your fixtures. A small leak won't always be visible—it may be in a buried line, inside a wall, or under a concrete slab.
The easiest check is to look at your water meter while no water is running in the house. If the meter dial is moving, water is leaking somewhere. Write down the meter reading, wait an hour without using water, and read it again. If the number changed, you're losing water.
Finding the exact location of a leak requires a plumber with leak detection equipment. They use acoustic sensors or dye tracing to pinpoint where water is escaping. Once found, the damaged section of pipe is cut out and replaced. The cost depends on where the leak is—a leak in an accessible basement line costs far less than one under a concrete foundation.
Know when to call a plumber
Call a plumber if your pressure regulator won't hold pressure after adjustment, if you suspect a leak in your main supply line, or if low pressure is confined to one room and cleaning the aerator didn't fix it. You should also call if pressure suddenly drops after being normal—this often signals a new leak or a regulator failure.
Before the plumber arrives, have your pressure gauge reading ready and be able to tell them whether low pressure is throughout the house or in one location. Let them know if you've already checked the meter valve and adjusted the regulator. This information helps them diagnose the problem faster.
Frequently Asked Questions
Can I increase water pressure by adjusting something other than the regulator?
Only if the meter valve is partially closed. Make sure the valve at the water meter is fully open—that's the first thing to check. After that, the regulator is the only adjustment point. Everything else that affects pressure (leaks, clogs, failed fixtures) requires repair, not adjustment.
What's the difference between a pressure regulator and a pressure tank?
A pressure regulator controls how high the pressure gets and protects your pipes from damage. A pressure tank (used in well systems) stores water and maintains pressure between pump cycles. If you're on city water, you have a regulator. If you have a well, you have a tank. They serve different purposes.
Is 50 psi too low for a shower?
Yes. Most showerheads need at least 60 psi to work properly. If your regulator is set to 50 psi, raise it to 65–70 psi. If pressure is still weak at the shower after adjustment, the problem is a clogged aerator, mineral buildup in the line, or a leak between the main line and the shower.
How often should I check my pressure regulator?
Check it once a year with a pressure gauge, especially if you notice pressure dropping slowly over time. A regulator that's working correctly will hold steady pressure for years. If you have to adjust it more than once a year, the diaphragm is wearing out and replacement is coming soon.
Can low water pressure damage my plumbing?
Low pressure itself doesn't damage pipes, but the cause of low pressure might. A leak will damage whatever is around the leak. A failed regulator that lets pressure spike too high can damage fixtures and connections. That's why it's worth finding and fixing the cause rather than just living with weak pressure.