Where the problem usually starts
Low water pressure in your home usually comes from one of three places: a problem with your water meter or the line from the street, a clogged aerator or valve inside your house, or mineral buildup in your pipes. The fastest way to find out which one is happening is to check whether the problem is everywhere or just one faucet.
If only one sink or shower has weak pressure, the issue is almost certainly inside that fixture — an aerator full of sediment or a shutoff valve that is not fully open. If pressure is low everywhere in the house, the problem is either in your main water line, your meter, or your pressure regulator. Start by calling your water company to ask if they have recorded low pressure on your street; if they have not, the problem is on your side of the meter.
Key Takeaways
- Low pressure in one faucet usually means a clogged aerator or a partially closed shutoff valve under that sink.
- Low pressure everywhere in the house points to your main shutoff valve, pressure regulator, or a leak in the line from the street.
- Cleaning an aerator takes five minutes and costs nothing; replacing a pressure regulator costs $150 to $300 and usually requires a plumber.
- A water meter that spins when all fixtures are off means you have a leak somewhere in your home's plumbing.
- Hard water mineral buildup in pipes is permanent without replacing the affected section, but a water softener can prevent future buildup.
Cleaning the aerator on a single faucet
An aerator is the small screen at the tip of your faucet. Over time, sediment and mineral deposits clog it and restrict flow. Unscrew the aerator by hand or with a wrench if it is stuck. Soak it in white vinegar for 30 minutes to dissolve mineral buildup, then scrub it with an old toothbrush and rinse it under running water.
Reassemble it and screw it back on. If the pressure is still low, the problem is deeper in the faucet or the shutoff valve. Check under the sink for a small valve with a handle or knob — this is the shutoff valve for that faucet. Turn it fully counterclockwise (or pull the handle all the way out if it is a lever). If pressure improves, the valve was partially closed and you have found your problem.
Checking your main water shutoff and pressure regulator
Your main shutoff valve is usually in the basement, crawlspace, or outside near the street. It controls water flow into your entire house. If it is a gate valve (a valve with a round handle), turn the handle counterclockwise until it stops. Do not force it. If it is a ball valve (a lever handle), make sure the lever is parallel to the pipe, not perpendicular to it.
Next to or very close to the main shutoff, you may see a pressure regulator — a bell-shaped or cylindrical device about the size of a soda can. A regulator that is set too low or has failed will reduce pressure throughout the house. You can test the pressure with a gauge you screw onto an outdoor faucet; normal household pressure is 40 to 80 pounds per square inch. If your gauge reads below 40 psi and your water company says their pressure is normal, the regulator has likely failed and needs replacement.
Finding a leak in your main water line
Turn off all water-using fixtures in your home — faucets, toilets, washing machine, everything. Go to your water meter and watch it for five minutes. If the dial or numbers change, you have a leak somewhere between the meter and your house, or inside your home's plumbing.
A leak in the line from the street is your water company's responsibility in most places, though some areas split the cost. Call your water company and report the leak; they will send someone to check the meter and the line. If the meter is not moving but pressure is still low, the problem is inside your house — likely a partially closed valve, a failed pressure regulator, or mineral buildup in older galvanized pipes.
Dealing with mineral buildup in old pipes
If your home was built before 1980 and has galvanized steel pipes, mineral deposits can accumulate inside the pipes over decades and gradually reduce pressure. This is especially common in areas with hard water. You cannot clear this buildup without replacing the affected pipes, which is expensive and usually requires a plumber.
A water softener will prevent new mineral buildup from forming, but it will not restore pressure that has already been lost to existing deposits. If you have hard water and want to slow future buildup, a softener costs $500 to $2,500 installed, depending on the size of your home and the type of system. For pressure problems caused by old galvanized pipes, pipe replacement is the only permanent fix.
When to call a plumber
Call a plumber if you have checked the aerators, the main shutoff valve, and the pressure regulator and pressure is still low, or if your pressure gauge reads below 40 psi and your water company confirms their pressure is normal. A plumber can test your pressure regulator, look for leaks you cannot see, and determine whether your pipes have mineral buildup or other internal damage.
Expect to pay $100 to $200 for a service call and diagnosis. If the regulator needs replacement, add $150 to $300 for the part and labor. If the problem is a leak in the main line or mineral buildup in pipes, costs will be higher and depend on how much of your plumbing needs repair or replacement.
Temporary fixes while you wait for a plumber
If pressure is low in one bathroom, close the shutoff valve under the sink halfway — this reduces flow to that fixture but may increase pressure elsewhere. If pressure is low everywhere, you can temporarily increase it by adjusting the pressure regulator if you have one. Locate the adjustment screw on top of the regulator and turn it clockwise a quarter turn, then test the pressure. Do not turn it more than a half turn, as excessive pressure can damage pipes and fixtures.
These are temporary measures only. A regulator that needs adjustment usually needs replacement within a few months. If you do not have a regulator or cannot locate one, there is no safe temporary fix — you will need a plumber to diagnose and repair the problem.
Frequently Asked Questions
Why is my water pressure low only in the morning?
Morning low pressure often happens because your water company is running maintenance or because demand is very high in your neighborhood. Call your water company and ask if they have scheduled work. If they do not, the problem is likely in your home — a pressure regulator that fails under high demand, or a partially closed valve that you can open fully.
Can I increase my water pressure myself?
You can clean aerators, open shutoff valves, and make a small adjustment to your pressure regulator if you have one. You cannot safely increase pressure beyond what your regulator is designed to allow. Pressure above 80 psi can damage pipes, water heaters, and fixtures. If your pressure is genuinely low and you have adjusted the regulator, a plumber needs to check whether the regulator itself has failed.
Does a water softener fix low pressure?
A water softener prevents future mineral buildup but does not restore pressure that has already been lost to existing deposits inside your pipes. If mineral buildup is the cause of your low pressure, a softener will stop it from getting worse, but you will still have low pressure until the affected pipes are replaced.
What does a pressure regulator do?
A pressure regulator reduces the water pressure coming from the street to a safe level for your home's pipes and fixtures. Most regulators are set to 50 to 60 psi. If the regulator fails or is set too low, pressure throughout your house will drop. If it is set too high, it can damage pipes and appliances.
How much does it cost to fix low water pressure?
Cleaning an aerator costs nothing. A plumber's service call costs $100 to $200. Replacing a pressure regulator costs $150 to $300. Fixing a leak in the main line or replacing mineral-clogged pipes costs significantly more and depends on how much of your plumbing is affected and how straightforward it is to access.