You need a pressure gauge to measure water pressure, and it costs $10 to $25

Water pressure is measured in pounds per square inch, or PSI. The only way to know your home's actual pressure is to attach a gauge to an outdoor faucet or hose bib and read the number. You cannot tell by how hard the water comes out of your shower — that feeling is unreliable and changes based on the faucet design.

A pressure gauge is a small brass or plastic device with a dial face. You screw it onto any outdoor faucet the same way you would attach a garden hose. The needle or digital display shows your pressure in seconds. Most hardware stores stock them in the plumbing section, and they cost between $10 and $25 depending on whether you want a dial or digital readout.

Normal household water pressure runs between 40 and 80 PSI. Anything below 40 PSI means weak flow; anything above 80 PSI can damage pipes, fixtures, and appliances over time. If your reading falls outside this range, you have a real problem to address — not a perception problem.

Key Takeaways

  • Buy a pressure gauge at any hardware store and screw it onto an outdoor faucet to get an when ready reading in PSI.
  • Normal water pressure is 40 to 80 PSI; readings below or above this range indicate a problem worth investigating.
  • Test your pressure when no other water is running in the house, because showers, toilets, and washing machines lower the reading temporarily.
  • If pressure is low, the problem is usually a closed valve, a clogged aerator, or an issue with your water supplier.
  • If pressure is high, you may need a pressure regulator installed to protect your plumbing from damage.

Where to attach the gauge and what to do before you test

Use an outdoor faucet — a hose bib on the side of your house, in the yard, or on a porch. Do not use an indoor sink or shower, because the gauge needs to be outside where water can drain freely. If you do not have an outdoor faucet, you can ask a plumber to install one, or you can test at a neighbor's house if they have one available.

Before you screw on the gauge, turn off all water use inside the house. Close the washing machine, stop the shower, turn off the dishwasher, and ask anyone else in the house to stay off the water for the next minute. Water pressure drops when multiple fixtures run at once, so testing during use gives you a false low reading. Wait two or three minutes after everything is off, then attach the gauge.

Open the outdoor faucet all the way and read the gauge. Leave it on for 10 to 15 seconds to make sure the needle or display has settled on a steady number. Write down what you see. That is your static pressure — the pressure when water is not actively flowing anywhere else in the house.

What to do if your pressure is too low

Low pressure — below 40 PSI — usually comes from one of three sources: a closed valve, a clogged aerator, or a problem on your water supplier's side.

Start by checking the main water shut-off valve, which is typically located where the water line enters your house from the street. It is usually in the basement, crawlspace, or under the kitchen sink. The valve has a handle that should point in the same direction as the pipe when it is fully open. If the handle is perpendicular to the pipe, the valve is partially or fully closed. Turn it to align with the pipe and test your pressure again.

If the main valve is already open, check the aerator on the outdoor faucet you tested. The aerator is a small screen at the tip of the faucet. Unscrew it by hand, hold it up to the light, and look for sediment, mineral buildup, or debris. If you see anything blocking the holes, soak the aerator in white vinegar for 30 minutes, then scrub it with an old toothbrush and rinse it. Screw it back on and test again.

If both of those are clear, the problem is likely with your water supplier. Call your local water department and report low pressure. They can check whether the issue is on their side of the meter or yours. If it is theirs, they will investigate. If it is yours and the valve and aerator are both clean, you may have a leak in your underground service line, which requires a plumber to locate and repair.

What to do if your pressure is too high

High pressure — above 80 PSI — puts stress on pipes, water heaters, washing machine hoses, and dishwashers. Over months or years, it can cause leaks, burst hoses, and premature failure of appliances. If your gauge reads above 80 PSI, you need a pressure regulator.

A pressure regulator is a valve that reduces incoming water pressure to a safe level. It is installed where the water line enters your house, usually right after the main shut-off valve. Some homes have one already; if yours does not, a plumber can install one in an hour or two. The cost is typically $300 to $500 including labor, depending on your location and how straightforward the installation is.

If you rent, contact your landlord or property manager. High pressure is their responsibility to fix, not yours. If you own the home, call a licensed plumber and ask for a pressure regulator installation. This is not a DIY job unless you have plumbing experience.

Understanding what the gauge is actually telling you

The number on the gauge is static pressure — the force of water sitting in your pipes when nothing is running. This is different from dynamic pressure, which is what you feel when water is actually flowing. A faucet that feels weak might have normal static pressure but poor flow because of a clogged aerator or a partially closed valve downstream.

Water pressure also varies throughout the day. It is often higher early in the morning and lower in the evening when more people are using water. If you test in the evening and get a reading of 75 PSI, that same faucet might show 85 PSI at 6 a.m. This is normal. Test at different times if you want to see the range, but one reading is usually enough to tell whether you have a real problem.

Pressure also drops slightly as water travels through your house. The pressure at the main shut-off valve is higher than the pressure at a second-floor bathroom faucet. This difference is usually small — 5 to 10 PSI — and not something you need to worry about unless you are troubleshooting a specific weak fixture.

When to call a plumber instead of testing yourself

If you do not have an outdoor faucet and do not want to install one, a plumber can test your pressure for you. They have the same gauges and will give you the same reading. The service call usually costs $75 to $150 depending on your area.

You should also call a plumber if your pressure is consistently above 80 PSI and you do not have a regulator, or if it is below 40 PSI and you have ruled out a closed valve and a clogged aerator. A plumber can check for leaks in your service line, test the regulator if you have one, and recommend repairs.

If you are renting and your pressure is outside the normal range, contact your landlord first. They are responsible for maintaining the water system. If they do not respond or refuse to fix it, you may have grounds to withhold rent or break the lease depending on your state's tenant laws — but that is a legal question, not a plumbing one.

Frequently Asked Questions

Can I use a tire pressure gauge to measure water pressure?

No. Tire gauges measure PSI but are not designed for water and will not fit onto a faucet. You need a water pressure gauge, which has a threaded connection that screws onto a standard outdoor faucet. They are inexpensive and sold at any hardware store.

What if my pressure is normal but the water still feels weak?

The problem is likely a clogged aerator, a partially closed valve on that specific faucet, or a design feature of the faucet itself. Check the aerator first by unscrewing it and looking for debris. If it is clean, try opening the shut-off valve under the sink all the way. If the faucet is old, it may straightforward have a low-flow design.

Do I need to turn off the water before I attach the gauge?

No. The gauge does not stop water flow; it just measures pressure. You do need to turn off all other water use in the house so the reading is not affected by showers or washing machines running elsewhere.

How often should I check my water pressure?

Once is usually enough unless you suspect a problem. If you notice weak flow, hear banging in the pipes, or see leaks, test again to see if pressure has changed. If you have a regulator, you do not need to test regularly — regulators are set once and last for years.

Can high water pressure cause my water bill to go up?

Yes. High pressure forces more water through your fixtures in the same amount of time, so you use more water per shower or per load of laundry. Installing a regulator can lower your water bill slightly while also protecting your pipes and appliances.