Plumbing guide
Low water pressure: one faucet or the whole house
By the Home Doctor team · Reviewed
Quick answer
First figure out whether it's one fixture or the whole house. Low pressure at one faucet or shower is usually a clogged aerator or showerhead that you can clean with vinegar for next to nothing. Low pressure everywhere points to a partly closed main valve, a failing pressure-reducing valve (typically $300 to $900 to replace), a hidden leak, old galvanized pipes, or a problem with the water supply. A sudden drop is worth a same-day leak check at your water meter.
- How urgent
- Fix soon
Low pressure at one faucet is an annoyance. A sudden whole-house drop can mean a leak, so check the meter the same day.
- DIY or pro
- DIY if handy
Cleaning aerators and showerheads and checking valves are simple DIY. A cartridge swap is a handy job. Pressure regulators, leak repairs and repiping are for a plumber.
Common causes and how to tell them apart
1. Clogged aerator or showerhead
- How to tell
- Only one faucet or shower is weak, and the flow sputters or sprays sideways. Common with hard water.
- What fixes it
- Unscrew the aerator or showerhead and soak it in white vinegar for an hour or more to dissolve the scale, or replace it.
2. Clogged or worn cartridge
- How to tell
- One fixture is still weak with the aerator off, or only its hot or cold side is weak.
- What fixes it
- Replace the cartridge. Bring the old one to the store to match it.
3. Partly closed valve
- How to tell
- The whole house is weak, often right after plumbing work. Or one fixture's shutoff under the sink isn't fully open.
- What fixes it
- Open the main shutoff and the fixture shutoffs fully. A round-handle valve turns fully counterclockwise. A lever-handle valve is open when the lever lines up with the pipe.
4. Failing pressure-reducing valve
- How to tell
- Pressure dropped across the whole house, slowly or all at once, and there's a bell-shaped valve on the main line where it enters the house.
- What fixes it
- A pressure gauge on a hose spigot confirms it. A plumber can adjust or replace the valve.
5. Hidden leak
- How to tell
- Pressure dropped suddenly, the water bill jumped, or you hear water running with everything off. The meter moves with every tap closed.
- What fixes it
- Find and repair the leak. A plumber can locate one that's inside a wall, under a slab or in the yard.
6. Old galvanized pipes
- How to tell
- Gray threaded steel pipes, usually in houses built before the 1960s. Pressure has slowly gotten worse everywhere, and the water may run rusty at first.
- What fixes it
- The pipes are closing up inside with rust and scale. Replacing them is the only real fix.
7. Water supply or well
- How to tell
- Neighbors have low pressure too, or there's work on the water main. On a private well, pressure is weak or surges and drops.
- What fixes it
- Call your water utility. On a well, a well contractor checks the pressure switch, pressure tank and pump.
Not sure which one you have?
Snap a photo. Home Doctor narrows it down, tells you how urgent it is, and prices the fix.
Diagnose it from a photoFirst diagnosis free. No account needed.
What you can safely try first
- 1Test several faucets, hot and cold, to see whether it's one fixture, one side, or the whole house. If it's the whole house, ask a neighbor if theirs is low too.
- 2Unscrew the aerator or showerhead and soak it in white vinegar.
- 3Check the shutoff valves under the sink and at the main, and make sure they're fully open.
- 4Screw a pressure gauge onto an outdoor hose spigot. Most homes run about 40 to 60 psi.
- 5Turn off every tap and water-using appliance, then watch the water meter for 15 minutes. If it moves, you have a leak.
When to call a pro
- The meter shows a leak and you can't find it.
- The whole house is low and all the valves are open.
- Your pipes are old galvanized steel and pressure keeps getting worse.
- You're on a well and pressure is weak or surging.
What it costs
| Job | DIY parts | Pro, installed |
|---|---|---|
| Clean or replace an aerator or showerhead | $0–$40 | — |
| Replace a faucet or shower cartridge | $15–$60 | $150–$350 |
| Replace a pressure-reducing valve | Not recommended | $300–$900 |
| Leak detection visit | — | $150–$500 |
| Repipe a house with galvanized pipes | Not recommended | $4,000–$15,000+ |
Ballpark US ranges as of September 27, 2026. Your region, access and the specifics of your home can move these a lot. Get two or three quotes for anything over a few hundred dollars.
What to tell the pro
I have low water pressure [at one faucet / on the hot side only / throughout the house]. It started [gradually / suddenly on (date)]. I've [cleaned the aerator / checked that the valves are fully open / tested with a gauge and got (reading) psi]. The meter [does / doesn't] move with everything off. The house was built around [year] and [has / doesn't have] a pressure-reducing valve.
Questions people ask
What is normal water pressure for a house?
Usually about 40 to 60 psi. Plumbing codes generally call for a pressure-reducing valve when street pressure is above 80 psi. A $10 to $20 gauge on a hose spigot tells you where you are.
Why is my water pressure suddenly low?
A sudden drop across the house usually means a closed or partly closed valve, a failed pressure-reducing valve, a leak, or work on the water main. Check with a neighbor, then check your meter for a leak.
Why is only my hot water pressure low?
If every hot tap is weak, look at the water heater: a partly closed valve on its pipes, or sediment built up in the tank and fittings. If it's one faucet, the hot side of its cartridge is the likely cause.
Can a pressure-reducing valve go bad?
Yes. They wear out and can fail low, giving weak pressure, or fail high, which can show up as banging pipes or a dripping relief valve on the water heater. A plumber can test and replace one.
Get an answer for your house
Every house is different. A photo gets you the likely cause, how urgent it is, and a fair price, in about 30 seconds.
Diagnose it from a photoFirst diagnosis free. No account needed.
General guidance, not a substitute for a licensed professional who can see the problem in person. If you smell gas, see sparks or smoke, or anyone is hurt, leave the area and call 911.