Where low pressure starts: the main shutoff valve and meter

The first place to check is your main water shutoff valve, usually located where the water line enters your house—often in the basement, crawlspace, or near the foundation. This valve controls all water flow into your home. If someone partially closed it, your pressure drops across every faucet and shower. Open it fully by turning the handle counterclockwise until it stops. If it is a gate valve (a round wheel handle), turn it slowly and stop when you feel resistance; forcing it can damage the valve.

Next, look at your water meter, which sits just after the main shutoff. Some meters have a small shutoff valve on the downstream side (the side closer to your house). If this valve is partially closed, it will restrict pressure throughout your home. Turn it fully open as well. If you cannot locate either valve or they are already open, move to the next step.

Key Takeaways

  • Check your main shutoff valve and meter valve first—both are often partially closed by accident and are the fastest fix.
  • A clogged water filter or sediment buildup in aerators can cut pressure to individual fixtures or your whole house depending on where the blockage is.
  • If pressure is low only at one faucet, clean or replace the aerator; if it is low everywhere, you may have sediment in your main line or a leak.
  • Water pressure regulators wear out over time and can be replaced by a homeowner with basic plumbing skills, though a plumber can do it faster.
  • A leak anywhere in your line—even a small one underground—will reduce pressure throughout the house and needs professional detection.

Cleaning aerators and screens on individual faucets

If pressure is low at only one sink, shower, or faucet, the problem is usually a clogged aerator—the small screen at the tip of the faucet. Sediment, mineral buildup, or debris gets trapped there and blocks flow. Unscrew the aerator by hand or with a wrench (wrap it in a cloth first so you do not scratch the finish). Rinse it under running water and use an old toothbrush to scrub away any white or brown deposits. If the screen is damaged or heavily corroded, replace it with a new one from a hardware store for a few dollars.

Shower heads work the same way. Unscrew the head from the arm and soak it in a bowl of white vinegar for 30 minutes to dissolve mineral deposits, then scrub the holes with a toothbrush. If holes are clogged solid, use a thin wire or needle to clear them. This fix often restores pressure to a single fixture without touching anything else in the house.

Replacing or cleaning your whole-house water filter

If pressure has dropped everywhere in the house at once, your whole-house water filter may be clogged. This filter sits on the main line after the meter and before the pressure regulator. A full filter blocks water flow to the entire house. Check your filter housing—it is usually a large cylindrical tank in the basement or utility room. Look for a pressure gauge on the side; if it reads above 20 psi (pounds per square inch), the filter needs replacement.

Replacing the filter cartridge is straightforward: turn off the main shutoff valve, open a faucet to release pressure, then unscrew the filter housing (use a filter wrench if it is tight). Pull out the old cartridge and slide in a new one rated for your water type—sediment filters are most common. Screw the housing back on, turn the water back on, and check for leaks at the connection. If you do not have a whole-house filter, skip this step.

Checking and adjusting your pressure regulator

Most homes have a water pressure regulator on the main line, usually a bell-shaped or cylindrical device just after the meter or filter. This valve reduces incoming pressure from the street (which can be 80 to 100 psi) to a safe level for your home's pipes and appliances (usually 40 to 60 psi). If the regulator is failing, pressure can drop too low or fluctuate wildly.

You can adjust a regulator yourself if you are comfortable with basic plumbing. Locate the adjustment screw on top of the regulator—it usually has a locknut around it. Turn the screw clockwise to increase pressure or counterclockwise to decrease it. Make small quarter-turn adjustments and check the pressure at a faucet with a pressure gauge (available at hardware stores for $10 to $20). Do not exceed 80 psi, as higher pressure damages pipes and appliances. If adjusting does not help or the regulator leaks, it needs replacement—a plumber can swap one out in under an hour, or you can do it yourself if you are handy with wrenches and have a bucket to catch water.

Detecting leaks in your main water line

A leak anywhere on your main water line—even a small pinhole underground—will reduce pressure throughout the house. Signs include a sudden drop in pressure, a wet spot in your yard or basement, or a hissing sound near the meter. If you suspect a leak, turn off all faucets and appliances, then check your water meter. If the meter is still running or the dial is moving, water is leaking somewhere.

Finding the exact location of an underground leak requires professional equipment. Call a plumber who has a leak detection service—they use acoustic listening devices or ground-penetrating radar to pinpoint the leak without digging. Once found, the line can be repaired or replaced. This is not a do-it-yourself job, but catching it early saves money and prevents foundation damage.

When to call a plumber instead of troubleshooting

If you have checked the main shutoff valve, meter valve, aerators, and filter, and pressure is still low, the problem is likely inside your plumbing system or the street line. A plumber can test your system pressure with a gauge, inspect the regulator, and check for leaks you cannot see. They can also determine whether the issue is on your side of the meter (your responsibility) or on the city's side (their responsibility).

Call a plumber right away if you see water pooling in your yard, hear water running when nothing is on, or if pressure drops suddenly after a freeze or after work on your street. These are signs of a serious leak or a break that will only get worse and more expensive to fix.

Frequently Asked Questions

Can low water pressure damage my appliances?

Low pressure alone does not damage appliances, but it can cause them to run longer or less effectively. Washing machines and dishwashers may not fill properly, and water heaters may struggle to deliver hot water. Fixing the pressure protects your appliances and saves water and energy.

Is there a normal water pressure I should aim for?

Most homes run best between 40 and 60 psi. Below 40 psi, showers feel weak and appliances underperform. Above 80 psi, pipes and fixtures wear out faster and you may hear banging in the walls. A pressure gauge costs $10 to $20 and lets you check your exact pressure at any faucet.

Why did my water pressure drop suddenly?

Sudden drops usually mean a valve was closed (check the main shutoff and meter valve first), a filter is clogged, or there is a new leak. If nothing is obviously wrong, a plumber can test the system and find the cause. Do not ignore a sudden drop—it often signals a problem that will worsen.

Can I increase pressure by adjusting the regulator myself?

Yes, if you have a pressure regulator and are comfortable turning a wrench. Make small adjustments and use a pressure gauge to check your work. Never exceed 80 psi. If you are unsure, a plumber can do it safely in minutes.

What if pressure is fine in winter but drops in summer?

Summer demand on the city water system can lower street pressure, especially in the afternoon. If your regulator is set too low, you will feel this drop more than your neighbors. Adjusting the regulator up slightly (within safe limits) can help. If the problem is severe, talk to your water utility—they may be able to increase pressure on your street.