You can measure your water pressure yourself with a straightforward $10 to $15 gauge

Water pressure is measured in pounds per square inch, or PSI. Most homes run between 40 and 80 PSI, and anything below 40 or above 80 usually means something needs adjustment. You do not need a plumber to find out where yours sits — a pressure gauge screws onto any outdoor faucet or hose bib in under a minute, and the reading appears on a dial.

Buy a gauge at any hardware store or online. Look for one labeled "water pressure gauge" with a range of 0 to 100 or 0 to 200 PSI. The dial type is easier to read than digital for a one-time test. Turn off all water use in the house first — no showers, washing machines, or sprinklers running — because active use changes the reading.

Key Takeaways

  • A water pressure gauge costs $10 to $15 and screws onto any outdoor faucet; the reading appears on a dial within seconds.
  • Turn off all water use in the house before testing so that showers, washing machines, and sprinklers do not skew the result.
  • Readings below 40 PSI usually mean a problem at the meter or in your main line; readings above 80 PSI can damage appliances and pipes over time.
  • Test at the faucet closest to where the water enters your house to get the most accurate picture of your incoming pressure.
  • If pressure drops when you turn on an indoor faucet, the problem is inside your home; if it stays the same, the issue is with your supply line.

Where to attach the gauge for the most accurate reading

The best place to test is the outdoor faucet closest to where the water line enters your house. This is usually on the side of the house nearest the street or the well. Testing here tells you the pressure of the water coming in before it splits into different lines for different rooms.

If you test at a faucet far from the entry point — say, a spigot on the back deck — the reading may be lower because water has already traveled through pipes and lost some pressure along the way. For a true picture of your incoming pressure, start at the point closest to the source.

Step-by-step: attaching the gauge and reading the result

First, turn off the water at the main shut-off valve inside your house or at the meter outside. This stops water from flowing while you attach the gauge. Open the outdoor faucet you chose to release any remaining water in the line, then close it again.

Unscrew the aerator — the small screen at the tip of the faucet — by turning it counterclockwise by hand. Screw the gauge onto the faucet threads where the aerator was. Turn the handle to the fully open position. The needle on the dial will jump to your PSI reading within a few seconds. Write down the number and turn the faucet off.

Unscrew the gauge, screw the aerator back on, and turn the main water back on. The whole process takes about five minutes.

What your reading means and when to worry

A reading between 40 and 80 PSI is normal and healthy. Water at this pressure flows well to all parts of your house without straining pipes or appliances. If your reading is below 40 PSI, water may trickle from showerheads and take a long time to fill a bathtub. If it is above 80 PSI, you may hear banging in the pipes when you turn off a faucet, and the extra force can wear out water heaters, washing machines, and dishwashers faster than normal.

Low pressure — below 40 PSI — usually points to a problem with the water company's supply line, a leak in your main line, or a partially closed shut-off valve. High pressure — above 80 PSI — is often caused by a faulty pressure regulator on your main line or by the water company itself. Both situations are worth investigating, though high pressure is more urgent because it damages equipment.

Testing pressure at different faucets to find where the problem is

If your main reading seems off, test a few other outdoor faucets to see if the problem is everywhere or just in one spot. If all outdoor faucets show the same low or high reading, the issue is with your incoming water supply. If one faucet reads normally but another reads low, the problem is in the pipes between them inside your house.

You can also test an indoor faucet by attaching the gauge to the kitchen sink faucet if it has a removable aerator. Turn off the main water, remove the aerator, attach the gauge, and turn the water back on. If indoor pressure is much lower than outdoor pressure, you may have a clogged pipe or a leak somewhere in your home's plumbing.

Common mistakes that throw off your reading

The biggest mistake is testing while water is running elsewhere in the house. A washing machine, shower, or sprinkler will pull water away from your test faucet and make the pressure read lower than it actually is. Always turn off all water use before you start.

Another common error is testing at a faucet with a clogged aerator. If the screen is full of mineral deposits, it restricts flow and makes pressure seem lower than it is. If a faucet reads much lower than others, remove and clean the aerator before concluding you have a pressure problem.

Do not forget to turn the main water back on after you finish. Some people attach the gauge and then leave it there, which blocks water from flowing to the rest of the house. Unscrew it and reattach the aerator as soon as you have your reading.

When to call a plumber about your pressure reading

If your reading is below 40 PSI and all faucets are affected, contact your water company first. They can tell you whether the problem is on their side of the meter. If they say pressure is normal at the meter, you have a leak or blockage in your main line, and a plumber can locate it with specialized equipment.

If your reading is above 80 PSI, a plumber can install or repair a pressure regulator on your main line. This is a relatively straightforward fix that protects your appliances. If pressure spikes suddenly — jumping from 60 to 100 PSI in a week — that also warrants a call, because it may signal a failing regulator or a change in your water company's supply.

Frequently Asked Questions

Do I need a special gauge or will any pressure gauge work?

Use a gauge labeled specifically for water pressure. Other gauges measure air pressure or gas pressure and have different scales. A water pressure gauge costs $10 to $15 at any hardware store and is designed to screw onto standard faucet threads.

What if my gauge does not fit the faucet?

Most outdoor faucets have the same thread size, but older homes sometimes have different sizes. If the gauge does not screw on, take it back and ask for an adapter. Hardware stores sell threaded adapters that fit most mismatches for a few dollars.

Can I test pressure from an indoor faucet if I do not have an outdoor one?

Yes, but remove the aerator first. Kitchen and bathroom sink faucets usually have removable aerators that unscrew by hand. Attach the gauge where the aerator was, turn the water on, and read the dial. This gives you an accurate indoor pressure reading, though it may differ slightly from outdoor pressure depending on your plumbing layout.

How often should I test my water pressure?

Test once a year or whenever you notice weak water flow or hear banging in the pipes. If you have already had pressure problems fixed, test again a few weeks later to confirm the repair worked.

What does it mean if pressure is fine one day but low the next?

Fluctuating pressure often means a leak somewhere in your system. Water escapes through the leak, and pressure drops. Call a plumber to locate the leak, or contact your water company if you suspect the problem is on their side of the meter.