Start with the simplest checks first

Low water pressure usually comes from one of three places: a closed valve, a clogged aerator, or a problem at the meter or main line. Before you call a plumber, spend ten minutes checking the obvious culprits. Most of the time, the fix takes no tools and costs nothing.

The first thing to do is turn on a cold-water tap in your kitchen and a hot-water tap in your bathroom at the same time. If cold water is fine but hot water is weak, the problem is in your water heater or the pipes feeding it—not your main supply. If both are weak everywhere in the house, the issue is upstream of your meter or in your main shutoff valve. If pressure is low in only one room or one fixture, the problem is local to that area.

Write down which fixtures have low pressure and which don't. This detail saves a plumber time and saves you money.

Key Takeaways

  • Check whether low pressure affects the whole house or just one fixture, because the location tells you where the problem is.
  • Look for a partially closed shutoff valve under the sink or at the water meter—this is the most common cause and takes seconds to fix.
  • Unscrew and clean the aerator (the screen at the tap tip) because mineral buildup blocks water flow without affecting pressure elsewhere.
  • If pressure is low everywhere and you rent, contact your landlord or water company; if you own, a plumber can test your main line for leaks or blockages.
  • Water heater problems show up as low hot-water pressure only, and usually mean sediment buildup or a failing dip tube inside the tank.

Check the shutoff valves under your sinks and at the meter

Every sink has a shutoff valve underneath it, usually two of them—one for hot water and one for cold. These valves look like small knobs or handles. If someone turned one partway closed, water flow drops to that fixture only. Turn both valves all the way counterclockwise (or pull the handle all the way toward you if it's a lever) and test the pressure again.

If that doesn't help, find your water meter. It's usually in a basement, crawl space, or buried in a box in your front yard. Next to the meter is a larger valve—your main shutoff. If it's partially closed, pressure will be low everywhere in the house. Turn it counterclockwise until it stops. Do not force it; if it's stuck, stop and call a plumber.

If you rent, ask your landlord or property manager to check the meter valve. They may have closed it partially to reduce water use or during a repair.

Clean the aerator on the affected tap

The aerator is the small screen at the end of your faucet. Mineral deposits from hard water build up inside it and block the flow. This happens most often in kitchens and bathrooms where you use hot water frequently. The fix takes two minutes.

Unscrew the aerator by hand (turn it counterclockwise). If it's stuck, wrap a cloth around it and use pliers, but don't crush it. Rinse it under running water and use an old toothbrush to scrub away white or brown deposits. If the screen is very clogged, soak it in white vinegar for 30 minutes, then scrub again. Screw it back on and test.

If you have low pressure at multiple taps, clean the aerators on all of them. If pressure is still low after cleaning, the blockage is deeper in the line.

Test whether the problem is in your water heater

Turn on a hot-water tap and let it run for 30 seconds. If the pressure is weak but the water gets hot, the problem is likely inside your water heater. Sediment collects at the bottom of the tank over time and can block the outlet pipe or damage the dip tube (a pipe inside the tank that delivers cold water to the bottom).

You can try flushing the water heater yourself if you're comfortable with basic plumbing, but this is one of the jobs where a plumber's time is worth the cost. A failed dip tube cannot be fixed without replacing the tank. If your water heater is more than 10 years old and hot-water pressure has dropped gradually, replacement is likely in your future anyway.

If cold water pressure is normal but hot water is weak everywhere in the house, call a plumber. Do not ignore this—a failing water heater can leak or fail suddenly.

Look for leaks in visible pipes

If pressure is low everywhere and the valves are open, water may be leaking from a pipe somewhere. Check under sinks, in the basement, and around the water heater for wet spots, stains, or dripping. Even a small leak reduces pressure throughout the house.

If you find a leak under a sink, you can try tightening the connection with a wrench. Turn the nut clockwise (righty-tighty). If tightening doesn't stop the leak, the connection needs a new washer or ferrule—a job for a plumber. If the leak is in a wall or underground, you will need a plumber to locate it and decide whether to repair or replace the section.

A leak in the main line between your meter and your house is the water company's responsibility in most places. Call them and report low pressure; they can check for leaks on their side of the meter.

When to call a plumber

Call a plumber if pressure is low everywhere in the house and you've checked the shutoff valves, cleaned the aerators, and found no visible leaks. A plumber can test your main line with a pressure gauge, check for blockages, and determine whether the problem is in your meter, your pipes, or the water company's supply line.

Bring your notes about which fixtures have low pressure and which don't. Tell the plumber whether the problem started suddenly or gradually, and whether you've had any recent work done on your plumbing. These details help them narrow down the cause.

If you rent, contact your landlord first. They are responsible for fixing problems in the building's plumbing. If the landlord doesn't respond, you may be able to contact your local housing authority or tenant rights organization.

Frequently Asked Questions

Why is my water pressure low only in the morning?

Low pressure in the morning often means the water company is doing maintenance or flushing the lines in your neighborhood. Pressure usually returns to normal within a few hours. If it doesn't, call the water company. If morning low pressure happens every day, a check valve in your meter may be failing—a plumber can test this.

Can I fix low water pressure myself without calling a plumber?

Yes, if the problem is a closed valve or a clogged aerator. These are the most common causes and take no special tools. If you've checked those and pressure is still low, the problem is likely in the main line, meter, or water heater—all jobs that need a plumber's tools and knowledge.

Does low water pressure mean I have a leak?

Not always. A leak is one cause, but closed valves and clogged aerators are more common. If you have a leak, you'll usually see wet spots or stains. A plumber can test your main line with a pressure gauge to tell the difference.

What should my water pressure be?

Normal household water pressure is between 40 and 80 pounds per square inch (PSI). If you want to know your exact pressure, a plumber can measure it with a gauge. Most people notice a drop when pressure falls below 40 PSI.

Is low water pressure a health hazard?

Low pressure itself is not a health hazard, but it can be a sign of a leak or a failing water heater. If pressure is very low and you have an older home, a plumber should inspect your pipes to rule out corrosion or damage.