You turn on the shower and get a weak trickle instead of a good spray. The kitchen faucet takes forever to fill a pot, and the washing machine seems to run longer than it used to. Low water pressure is one of the most common plumbing complaints, and it can come on slowly over years or drop overnight.
The fix depends on where the problem is. This guide helps you work out whether it’s the whole house or a single fixture, how to test your pressure with a simple gauge and what the reading means, and how to check the main shutoff, pressure regulator, pipes, aerators and well system. It also covers hidden leaks and when to bring in a plumber.
Quick answer: If only one faucet or shower is weak, clean its aerator or showerhead and check the shutoff valve under it. If the whole house is weak, make sure the main shutoff is fully open, then test the pressure at an outdoor spigot with a gauge. A reading well below 35 to 60 psi usually points to a failing pressure regulator, a supply problem, a leak or old corroded pipes.
Start here: is it the whole house or one fixture?
Before you buy anything, walk through the house and turn on a few cold and hot taps on different floors. The pattern tells you where to look.
| What you notice | Most likely causes | Check first |
|---|---|---|
| One faucet or shower is weak, others are fine | Clogged aerator or showerhead, partly closed fixture valve, worn cartridge | Unscrew and clean the aerator or showerhead |
| Only hot water is weak, everywhere | Water heater valve partly closed, sediment in the heater or its outlet | Shutoff valve on the water heater cold inlet |
| Everything is weak, all the time | Main valve partly closed, failing pressure regulator, corroded pipes, low street pressure | Main shutoff, then a pressure gauge test |
| Pressure dropped suddenly everywhere | Utility main break or work, frozen pipe, major leak | Ask neighbors, call the water utility, check the meter |
| Pressure fades in the morning and evening | Peak demand on the city system, undersized pipes | Gauge readings at different times of day |
| House is on a well | Pressure switch, pressure tank, clogged filter, aging pump | Pressure gauge at the tank and the filter cartridge |
How to test your water pressure
A screw-on water pressure gauge from any hardware store is the single most useful tool for this problem. It turns guesswork into a number you can act on.
- Turn off every faucet, shower, sprinkler and water-using appliance in the house.
- Screw the gauge onto an outdoor hose spigot near where the water line enters the house, or onto the washing machine cold faucet.
- Open the spigot fully and read the gauge. This is your static pressure.
- Have someone open a tub faucet inside. If the reading drops sharply, the pipes may be restricted or undersized.
- Repeat at a busy time, such as early morning, to see if street pressure dips.
Here’s how to read the result. The Las Vegas Valley Water District notes that most plumbing professionals recommend setting a pressure regulator between 35 and 60 psi, and that sustained pressure above 80 psi can damage plumbing.
| Gauge reading | What it means |
|---|---|
| Below about 35 psi | Low. Showers and appliances will feel weak. Look for a regulator, valve, pipe or supply problem. |
| 35 to 60 psi | The range most plumbers aim for. If a fixture still feels weak, the problem is local to it. |
| 60 to 80 psi | Strong. Fine for most homes, but harder on fixtures and appliances over time. |
| Above 80 psi | Too high. The Uniform Plumbing Code calls for a pressure regulator at this level. |
Causes of low pressure throughout the house
The main shutoff or meter valve isn’t fully open
This is the easiest fix and is often overlooked after plumbing work. Find the main shutoff where the water line enters the house, often in the basement, garage, crawlspace or near the water heater. A lever-style ball valve is fully open when the handle runs parallel to the pipe. A round gate valve should be turned fully counterclockwise.
There may also be a valve at the meter, typically in a box near the street. That one usually belongs to the utility, so call them rather than forcing it yourself.
A failing or misadjusted pressure regulator
Many homes have a pressure reducing valve (PRV), a bell-shaped brass valve on the main line just after the shutoff. It lowers high street pressure to a safe level. When it wears out, pressure can drop, fluctuate or creep too high.
Most regulators have an adjusting screw on top with a locknut. On most models, turning the screw clockwise raises pressure.
Loosen the locknut, turn the screw a quarter turn at a time, open a faucet to settle the pressure, and recheck your gauge. If adjusting does nothing, the regulator has probably failed. Angi puts their typical lifespan at 10 to 15 years.
A regulator can only reduce pressure. It can’t push the reading higher than what the street provides.
Low pressure from the water utility
If neighbors are having the same problem, the cause may be a main break, hydrant flushing, repair work or heavy demand. Your utility can tell you what pressure to expect at your address, and many will check it for you. Homes at the top of a hill or far from the supply often get lower pressure, and a booster pump is sometimes the only fix.
Corroded galvanized or aging pipes
Galvanized steel pipes, common in older homes, rust from the inside. Over decades, the buildup narrows the opening until only a fraction of the original flow gets through. Signs include weak pressure that’s worse on upper floors, rusty or brown water after the water sits, and leaks at threaded joints.
To check, look at exposed pipes near the water heater or main. Galvanized pipe is dull gray, has threaded fittings, and a magnet will stick to it; copper and plastic won’t attract a magnet. Replacing sections or repiping the house is the only real fix.
A hidden leak
A leak in the service line, slab or a wall diverts water and lowers pressure. Turn off all water in the house and watch the meter for 15 minutes or so. If the dial or leak indicator moves, water is escaping somewhere. Wet spots in the yard, a hissing sound or a sudden spike in your bill are other clues.
A frozen pipe
In late fall and winter, a sudden drop at certain fixtures can mean a partly frozen pipe in an exterior wall, crawlspace or garage. Never use an open flame to thaw it. See our guide on how to prevent frozen pipes for safe thawing and protection.
A clogged whole-house filter or softener
Sediment filters and water softeners sit on the main line, so a clogged cartridge or failing softener valve slows water to the whole house. Put the unit in bypass mode. If pressure jumps back, replace the cartridge or service the softener.
Causes of low pressure at one fixture
Clogged aerator or showerhead
Minerals and debris collect on the small screen at the tip of the faucet and in showerhead nozzles. Unscrew the aerator (wrap it in a cloth to protect the finish), rinse the screen, and soak it in white vinegar for an hour if it’s crusty. Our guide on how to clean a shower head covers showers step by step.
A partly closed shutoff or worn cartridge
Check that the valves under the sink or behind the toilet are fully open. If the aerator is clean and the valves are open, debris may be stuck in the faucet cartridge. Shut off the water, remove the cartridge, rinse it and the faucet body, and reinstall it, or replace it if it’s worn.
Weak hot water only
If the hot side is weak at every tap but cold is fine, check that the valve on the water heater’s cold inlet is fully open. Sediment in the tank and corroded heater nipples can also restrict flow. Flushing often helps; follow our guide to flushing a water heater.
A kinked or failing supply line
Flexible supply lines under sinks and behind toilets can kink when items in the cabinet push against them, and old ones can collapse inside. Replace any line that’s kinked, bulging or more than a few years old with a braided stainless one.
Low water pressure on a private well
Well systems make their own pressure. A pump fills a pressure tank, and a pressure switch turns the pump on and off. According to the University of Nebraska-Lincoln Extension, the pump typically shuts off at 40 to 60 psi and restarts at 20 to 40 psi.
- Check the gauge at the tank. If pressure stays near the low setting, the switch, pump or well yield may be the problem.
- Check the tank’s air charge. UNL Extension notes most manufacturers recommend about 2 psi below the pump-on pressure. Check it with the pump power off and the tank drained. A waterlogged tank makes the pump click on and off rapidly.
- Change the sediment filter. A clogged cartridge after the tank is one of the most common causes of weak well pressure.
- Watch for dirty contacts or a failing pump. Sputtering faucets, air in the lines or a pump that runs constantly need a well contractor.
Safety note: A well pressure switch carries line voltage, often 240 volts. Switch off the pump’s breaker before you remove the switch cover or touch the tank’s air valve, and leave electrical repairs to a qualified well contractor or electrician.
Tools and materials
- Water pressure gauge with a hose thread fitting
- Adjustable wrenches (two, for holding and turning)
- Flathead screwdriver
- White vinegar and a small container for soaking aerators
- Soft cloth or tape to protect fixture finishes
- Replacement aerators, filter cartridges or braided supply lines as needed
- Tire pressure gauge (for checking a well tank’s air charge)
Pro tip: Don’t crank a regulator to the maximum to fix weak showers. If it’s failing, it may suddenly let full street pressure through, which can stress fixtures and cause banging pipes and water hammer. Adjust in small steps and stay under about 60 psi.
When to call a pro
Call a licensed plumber, or a well contractor for well systems, if you notice any of these:
- Your gauge reads low, the main valve is fully open and adjusting the regulator doesn’t help.
- Pressure is over 80 psi, or the water heater’s relief valve is dripping.
- The meter moves with all water off, or you find wet spots in the yard or on the slab.
- You have galvanized pipes with rusty water or repeated leaks.
- A well pump runs constantly, short-cycles or the water sputters.
Angi lists pressure regulator replacement at typically $200 to $700, with an average of about $400, and plumber labor around $75 to $200 an hour. Repiping costs much more: Angi’s repiping guide puts it at typically $1,500 to $15,000, with an average near $7,500, depending on the size of the house and pipe material.
Frequently asked questions
Why did my water pressure suddenly drop?
A sudden drop across the whole house usually means utility work, a main break, a frozen pipe or a large leak. Ask a neighbor if they’re affected and call your water utility. If it’s only your house, check the main valve and look at your meter for signs of a leak.
Why is my shower pressure low when the rest of the house is fine?
A clogged showerhead is the most likely cause, followed by a flow restrictor in the head or a worn shower valve cartridge. Clean the showerhead first. If that doesn’t help, the cartridge or a mixing valve may need service.
What psi should my house water pressure be?
Most plumbers recommend 35 to 60 psi, and many homes feel best around 50. Anything above 80 psi is too high and calls for a pressure regulator. Below about 35 psi, most people notice weak showers and slow fills.
Can a water heater cause low water pressure?
Yes, but only on the hot side. A partly closed inlet valve, sediment in the tank or corroded fittings can restrict hot water flow. If cold water is fine and hot is weak everywhere, start at the water heater.
How can I increase my water pressure?
Clean aerators and showerheads, open the main valve fully and adjust the pressure regulator slightly if you have one. If the street pressure itself is low, a plumber can install a booster pump. Old galvanized pipes need replacing to get full flow back.
The bottom line
Start simple: check whether the problem is in one fixture or the whole house, clean the aerator or showerhead, and make sure the main valve is fully open. Then test with a pressure gauge, aiming for 35 to 60 psi. If the reading is low and a small regulator adjustment doesn’t fix it, a failing regulator, hidden leak or corroded pipe is likely, and that’s the time to call a plumber.
