What causes low water pressure and how to fix it
Low water pressure usually comes from one of three sources: a problem inside your home that you can fix yourself, a problem between your meter and your home that requires a plumber, or a problem with your municipal water supply that you cannot fix. Start by checking whether the problem is everywhere in your house or only at certain fixtures. If only your kitchen sink has weak pressure, the issue is local — a clogged aerator or a valve you can replace in minutes. If your whole house has low pressure, the problem is either in your main water line, your pressure regulator, or your municipal supply.
The fastest way to know which is which: call your water department and ask whether they are experiencing pressure issues in your area. If they say no, the problem is yours to solve. If they say yes, you are waiting for them to fix it — there is nothing you can do on your end.
Key Takeaways
- A clogged aerator on a single faucet takes two minutes to clean and costs nothing; unscrew it, rinse it under running water, and screw it back on.
- If low pressure affects your whole house, check your pressure regulator — a bell-shaped valve usually located where the main water line enters your home — and have a plumber adjust or replace it if it is faulty.
- Mineral buildup in pipes and fixtures is common in hard water areas and requires either chemical cleaning or replacement of the affected section.
- Municipal water pressure problems are outside your control; contact your water department to confirm whether the issue is on their side before spending money on repairs.
Clean or replace the aerator on a single weak faucet
An aerator is the small screen at the tip of your faucet. Sediment, mineral deposits, and debris collect inside it and block water flow. If only one faucet has low pressure, this is almost always the culprit.
Unscrew the aerator by hand — it usually twists off counterclockwise. If it is stuck, wrap a cloth around it and use pliers. Rinse the aerator under hot running water and use an old toothbrush to scrub away any visible buildup. If the screen is corroded or damaged, replace it with a new one that matches your faucet brand and size; they cost between $3 and $15 at any hardware store. Screw the new aerator back on by hand until it is snug, then test the pressure.
If cleaning the aerator does not help, the problem may be inside the faucet itself. Mineral deposits can build up in the valve cartridge. Some cartridges can be soaked in vinegar overnight to dissolve the deposits; others need to be replaced. Check your faucet's manual or search the model number online to see which type you have.
Check your main water shut-off valve and pressure regulator
Your main water shut-off valve is located where the water line enters your home, usually in the basement, crawl space, or under the kitchen sink. It looks like a lever or a round knob. If someone has partially closed this valve, your whole house will have low pressure. Make sure it is fully open — the lever should point in line with the pipe, or the knob should turn counterclockwise until it stops.
Next to or near the shut-off valve, look for a pressure regulator — a bell-shaped or cylindrical device about the size of a fist. This valve automatically reduces pressure from the street to a safe level for your home's pipes. If it fails, pressure drops throughout the house. You can test it with a pressure gauge, which you can buy or rent from a hardware store for $10 to $30. Screw the gauge onto an outdoor faucet or a washing machine outlet and turn on the water. Normal household pressure is between 40 and 80 pounds per square inch (psi). If your gauge reads below 40 psi, the regulator may be failing.
A faulty pressure regulator must be replaced by a plumber. The job usually costs between $150 and $300 in labor and parts. If your regulator is working but pressure is still low, the problem may be in the main line itself — a leak, corrosion, or blockage — which also requires a plumber to diagnose and repair.
Address mineral buildup in pipes and fixtures
Hard water — water with high levels of calcium and magnesium — leaves mineral deposits inside pipes and fixtures over time. This buildup narrows the pipe opening and reduces flow. If you live in a hard water area and have gradually noticed pressure dropping over years, mineral accumulation is likely the cause.
For a single fixture, soak the affected part in white vinegar overnight. For a showerhead, unscrew it and submerge it in a bag of vinegar tied around the fixture. For a faucet aerator, soak it in a cup of vinegar. The acid dissolves mineral deposits. Scrub with an old toothbrush and rinse thoroughly before reinstalling.
If mineral buildup is widespread throughout your home, you have two options. A water softener removes minerals from all incoming water and prevents future buildup; systems range from $500 to $2,500 installed and require ongoing salt or potassium refills. Alternatively, a plumber can flush your main line with a chemical solution designed to dissolve deposits, though this is temporary and buildup will return over time. For severe cases, sections of corroded pipe may need to be replaced.
Install a booster pump if pressure is consistently low
If your water pressure is naturally low because your home is at high elevation or far from the municipal water source, and you have ruled out regulator failure and blockages, a booster pump can increase pressure throughout your home. These pumps are installed on the main water line after the meter and automatically set up when you turn on a faucet.
Booster pumps cost between $300 and $800 installed, depending on size and flow rate. A plumber will size the pump based on your home's needs and your current pressure reading. The pump requires electricity and occasional maintenance, but it is a permanent solution if low pressure is a chronic problem in your area.
Before investing in a booster pump, confirm with your water department that your municipal pressure is genuinely low and not temporary. Some areas have seasonal pressure variations or planned maintenance that temporarily reduces flow.
Verify the problem is not on the municipal side
Call your local water department and report low pressure. Ask whether they are experiencing issues in your neighborhood or service area. Many departments have online outage maps or automated phone lines that tell you this in seconds. If the department confirms a problem on their end, you have no repair to make — pressure will return once they fix the issue.
If the department says pressure is normal on their side, the problem is in your home or the line between your meter and your house. This is your responsibility to fix. Ask the department whether they can send someone to test the pressure at your meter; some departments offer this service for free or a small fee. This test tells you definitively whether the problem started before or after your meter, which narrows down where a plumber should look.
When to call a plumber versus handling it yourself
Clean an aerator or check your shut-off valve yourself — these take minutes and cost nothing. If pressure does not improve after cleaning, or if low pressure affects your whole house, call a plumber. Diagnosing problems in the main water line, pressure regulator, or buried pipes requires specialized tools and knowledge.
Get a quote from at least two plumbers before committing. Most will charge a diagnostic fee of $75 to $150, which they may credit toward repair costs if you hire them. Ask whether they can test your pressure and identify the exact problem before quoting a repair price. A plumber who can pinpoint the issue — a failed regulator, a leak, mineral buildup, or a blockage — will give you an accurate estimate and help you decide whether repair or replacement makes sense for your situation.
Frequently Asked Questions
Can low water pressure damage my pipes or appliances?
Low pressure itself does not damage pipes, but the underlying cause might. A leak in your main line wastes water and can erode soil around your foundation. Mineral buildup that reduces pressure also reduces flow to water heaters and washing machines, making them work harder. Have a plumber identify the cause so you can address it before secondary damage occurs.
Why is my water pressure low only in the morning?
Morning pressure dips are common when many households in your area use water at the same time. This is a municipal supply issue, not a problem with your home. Pressure usually returns to normal by mid-morning. If pressure stays low all day, the problem is in your home or your service line.
Does a water softener increase pressure?
No. A water softener removes minerals but does not increase flow rate. It may slightly improve pressure in homes with severe mineral buildup by preventing future deposits, but it will not solve an when ready pressure problem. Install a softener to prevent buildup over time, not to fix current low pressure.
How much does it cost to fix low water pressure?
Cleaning an aerator costs nothing. Replacing a pressure regulator runs $150 to $300. A booster pump costs $300 to $800 installed. Plumbing diagnostics cost $75 to $150. Costs vary by region, plumber, and the underlying problem. Get quotes from multiple plumbers before deciding.
Can I increase water pressure by adjusting my pressure regulator myself?
Pressure regulators have an adjustment screw, but turning it without a pressure gauge can damage your pipes or fixtures. Pressure above 80 psi stresses plumbing and appliances. Have a plumber adjust it if you want to change your pressure setting.