Where the problem starts: main shutoff, meter, and regulator

Low water pressure usually comes from one of three places: the main shutoff valve is partially closed, the pressure regulator is set too low, or sediment is blocking the line. Before you call a plumber, check these three things in order, because the first two take minutes and cost nothing.

The main shutoff valve is typically located where the water line enters your house — often in the basement, crawl space, or outside near the foundation. It looks like a handle or knob on a pipe. If it is a ball valve (a lever handle), make sure it points in line with the pipe. If it is a gate valve (a round knob), turn it counterclockwise until it stops, then back it off a quarter turn. A valve that is even slightly closed will cut your pressure in half.

After the main shutoff, water passes through a pressure regulator — a bell-shaped or cylindrical device on the pipe, usually within three feet of where the water enters. This device is set at the factory to around 50 to 60 pounds per square inch (psi). If someone has adjusted it downward, that is your problem. Look for a screw or bolt on top of the regulator. Turn it clockwise to increase pressure, but do not exceed 80 psi, which can damage fixtures and appliances.

Key Takeaways

  • Check that your main shutoff valve is fully open — a partially closed valve is the most common cause of low pressure and takes seconds to fix.
  • If you have a pressure regulator, turning the adjustment screw clockwise will increase pressure, but do not go above 80 psi.
  • Sediment buildup in the line requires flushing or replacing the water meter, which usually means calling your water utility or a plumber.
  • If pressure is low in only one room or fixture, the problem is likely a clogged aerator or a closed shutoff valve under that sink or behind that toilet.
  • Water pressure naturally drops if you are running multiple fixtures at once — this is normal and does not require repair.

Sediment in the line: when flushing helps and when it does not

If the shutoff valve is open and the regulator is set correctly, sediment or mineral buildup inside the water meter or supply line is the next likely culprit. You can try flushing the line yourself by turning off the main shutoff, opening the lowest faucet in your house (usually a basement sink or outdoor spigot), and letting it run for a few minutes once you turn the water back on. This sometimes dislodges loose sediment.

If flushing does not work, the meter itself may be clogged. Call your water utility — they own the meter and can clean or replace it at no cost to you. If the utility rules out the meter, sediment is trapped deeper in the line, and a plumber can install a whole-house water filter or flush the line with high-pressure equipment. This typically costs between $300 and $800 depending on how far the blockage is from the house.

Low pressure in one room or one fixture

If water pressure is normal everywhere else in the house but weak in one sink, shower, or toilet, the problem is local to that fixture. Start by checking the shutoff valve under the sink or behind the toilet — it may be partially closed. Turn it all the way counterclockwise.

Next, clean the aerator, which is the screen at the tip of the faucet. Unscrew it by hand or with a wrench, rinse it under running water, and use an old toothbrush to scrub away mineral deposits. If the aerator is heavily corroded, replace it — they cost $3 to $10 at any hardware store. For shower heads, soak the head in a bowl of white vinegar for an hour, then scrub and rinse. If the fixture is still weak after cleaning, the shutoff valve itself may be failing and will need replacement by a plumber.

When multiple fixtures are weak at the same time

If you notice pressure drops when you run the dishwasher and shower at the same time, or when someone is watering the lawn, that is normal. Your house has a limited flow rate — the total amount of water that can move through the main line at once. This is usually 15 to 25 gallons per minute. When you exceed that, pressure drops everywhere.

You cannot increase the total flow rate without upgrading the main water line, which is expensive and requires digging. Instead, stagger your water use: run the dishwasher at night, avoid showers when the sprinklers are on, or install a second water meter if you have a large property. If you want higher pressure for a specific fixture like a shower, a pressure-boosting pump can help, but it adds $1,000 to $2,000 to your plumbing system.

Pressure-boosting pumps: when they make sense

A pressure-boosting pump is a device that sits on your main water line and increases pressure throughout the house. These pumps cost $1,000 to $2,500 installed and are most useful if your water utility supplies pressure below 40 psi or if you live at the top of a hill where gravity naturally reduces pressure. They are not useful if your pressure is already 50 psi or higher, because the problem is usually something else.

Before you buy a pump, have a plumber measure your actual pressure with a gauge. Screw the gauge onto an outdoor spigot and read the number. If it is below 40 psi and the shutoff valve is open, a pump may help. If it is 50 psi or higher, a pump will not solve your problem, and you should focus on the regulator, sediment, or local fixture issues instead.

What a plumber will check if you call one

If you have tried the steps above and pressure is still low, a plumber will start by measuring pressure at the meter and at different points in the house. This tells them whether the problem is on the utility side (their responsibility) or on your side (yours). They will also check for leaks, which can reduce pressure without you noticing — a slow leak in a wall or under the foundation will make the system work harder and deliver less water to your fixtures.

A plumber may also recommend a water softener if you live in a hard-water area, because mineral buildup in pipes and fixtures reduces flow over time. Water softeners cost $500 to $2,500 installed and last 10 to 15 years. They are worth considering if you have low pressure and hard water, but they are not a quick fix.

Frequently Asked Questions

Is 60 psi good water pressure?

Yes. Most homes are comfortable between 50 and 80 psi. Below 50 psi, showers feel weak and dishwashers run slowly. Above 80 psi, you risk leaks in pipes and damage to water heaters and washing machines. If your pressure is 60 psi and you are still unhappy, the problem is likely a clogged aerator or a fixture-specific issue, not the main line.

Can I adjust the pressure regulator myself?

Yes, if you can locate it and identify the adjustment screw. Turn it clockwise to increase pressure, but do not exceed 80 psi. If you cannot find the regulator, do not have one, or are unsure, call a plumber — they can adjust it in 15 minutes for $75 to $150. It is cheaper than guessing.

Why is my water pressure low only in the morning?

Your utility may be flushing the main line or performing maintenance early in the morning. This is temporary and should resolve by mid-morning. If it happens every morning, call your water utility to ask about their schedule. If it is not scheduled maintenance, low morning pressure can signal a leak that opens and closes with temperature changes — a plumber can locate it with a pressure test.

Does a whole-house water filter reduce pressure?

Yes, slightly. A filter adds resistance to the line, which can drop pressure by 5 to 10 psi. If your pressure is already low, installing a filter will make it worse. Install a filter only if your pressure is 60 psi or higher, or pair it with a pressure-boosting pump.

How much does it cost to fix low water pressure?

If the problem is a closed shutoff valve or a regulator adjustment, it costs nothing. Cleaning an aerator costs $0 to $10. Flushing a line costs $200 to $400. Replacing a water meter costs $0 (utility pays) to $500 (if done by a plumber). A pressure-boosting pump costs $1,000 to $2,500 installed. A plumber visit to diagnose the problem costs $75 to $150.