How to Test Your Water Pressure at Home in 5 Minutes
Published November 7, 2026 · San Antonio Water Pressure Pros
You do not need a plumber to find out what your water pressure is. A screw-on gauge costs about $10 to $15 at a hardware store, and the test itself takes about five minutes. Here is how to do it, what the numbers mean, and when the numbers tell you to call someone.
What You Need
The test needs one tool: a screw-on pressure gauge. It is a dial gauge that threads onto an outdoor spigot, the same kind of spigot you connect a garden hose to. You can find one at any hardware store for about $10 to $15. Some gauges have a second, red needle that stays at the highest reading — handy if your pressure spikes while you are not looking. Either type works for this test.
You also need an outdoor hose bib, ideally the one nearest where the main water line enters your home, and five minutes when nobody in the house needs water. That last part matters: any water running during the test will give you a low reading that means nothing.
The 5-Minute Test, Step by Step
- Turn off all the water in the house. Every faucet, the washing machine, the dishwasher, the sprinklers, and the ice maker. If anything is running, the gauge will read low and the number will be useless.
- Screw the gauge onto the hose bib. Hand-tight is enough. Do not force it with a wrench — a snug fit seals fine, and a wrench can crack the fitting.
- Open the hose bib all the way. The needle will jump, then settle. Give it a few seconds.
- Read the static pressure. This is the reading with no water running anywhere in the house. Write it down. This number is what the street is delivering to your home.
- Open a faucet inside the house and read the gauge again. This is the running pressure — the number that matters when water is actually being used. If it falls hard when a faucet opens, the pipes cannot carry the volume. Write this number down too.
- Close the faucet, close the hose bib, and unscrew the gauge. You now have two numbers: static pressure and running pressure. Together they tell you more than either one alone.
Reading the Results
Pressure is measured in PSI — pounds per square inch. Here is how to read the numbers on your gauge:
| Gauge reading | What it means |
|---|---|
| Below 40 PSI | Low. Fixtures will feel weak, and the cause is worth finding. |
| 40 to 60 PSI | The range most homes are built for. This is the commonly recommended range for household pressure. |
| 61 to 80 PSI | High end. Usable, but worth watching. Above 80 PSI a pressure regulator is needed. |
| Above 80 PSI | Too high. SAWS recommends a maximum of 80 PSI, especially if you have a water softener or a sprinkler system. |
Two things to keep in mind. First, the 40 to 60 range is commonly recommended guidance for household pressure — it is not a rule set by SAWS. SAWS says pressure in its service area can range from 35 to 175 PSI, a wide spread because pressure depends on elevation and distance from the mains. Your street's normal may be different from another street's. Second, a single reading is a snapshot. Pressure can vary during the day as demand on the street main rises and falls. A swing of a few PSI is normal. A swing of 20 PSI or more, or pressure that falls every time a second fixture runs, points to a restriction inside your home.
If your reading is low, the next step is to find out where the pressure is being lost. That is what water pressure testing and diagnosis does — measuring at the main and at fixtures to trace the drop to its source.
What to Do If It Reads Below 40
A low reading is the start of the diagnosis, not the end of it. Check the simple things first:
- Is the main shutoff valve fully open? A valve left half open after any work throttles the whole house. Check the handle — on a ball valve, the handle should sit parallel to the pipe when it is open.
- Is it one fixture or all of them? One weak faucet with the rest of the house fine usually means a clogged aerator or a worn cartridge at that fixture. See fixture low pressure repair.
- Do your neighbours have the same problem? If the houses around you are low too, the cause may be on the street side. If yours is the only weak house, the cause is inside your property.
- Has the pressure been falling slowly for months? A slow decline points to scale or old pipe narrowing from the inside — San Antonio water runs about 280 to 300 parts per million, and that hardness leaves scale in pipes year after year. See pipe descaling.
- Has your water bill risen too? A higher bill along with low pressure can mean a hidden leak bleeding pressure away before it reaches your fixtures.
What to Do If It Reads Above 80
High pressure is a problem too, and it is often silent — no weak shower to warn you. Pressure above 80 PSI stresses pipes, fixture seals, and appliance supply lines. It can cause banging pipes when a faucet closes, dripping faucets, and running toilets.
The fix is usually the pressure regulator. The PRV is the bell-shaped valve on the main line where water enters your home, and its job is to step street pressure down to a safe, steady level. If you have one, it may need adjusting or servicing. If you do not have one and your pressure reads high, a regulator is the fix. See pressure regulator repair and replacement for what that job involves and what it typically costs ($300–$650).
When a Gauge Reading Is Not Enough
A gauge on a hose bib measures static pressure — the push in the pipes when nothing is running. That is useful, but it is only half the picture. A pipe narrowed by scale or rust can show a healthy static reading and still collapse when a tap opens, because the pipe cannot carry the volume. That is why the running reading in step 5 matters: if the needle falls hard when water runs, the restriction is inside your home's pipes.
A plumber tests both. Static pressure at the main, running pressure at several fixtures, and the regulator's behaviour under load. If your gauge readings are confusing — normal at rest, weak in use, or different at every fixture — that is the point where professional testing earns its keep. You have already done the useful first step by measuring; testing finds where the pressure goes after the gauge.
And if your gauge reads fine everywhere but the shower still runs weak, the problem is probably at the fixture, not in the system. See our guide to low water pressure room by room for how to work through the rooms one at a time.
Call San Antonio Water Pressure Pros
Tell us what your water pressure is doing, and we will talk through what happens next and set a time to come to your home.
14570 Calaveras Creek, San Antonio, TX 78223
Frequently Asked Questions
Do I need a special gauge to test my water pressure?
No. A basic screw-on dial gauge from a hardware store is enough — about $10 to $15. It should thread onto a standard outdoor hose bib, which almost all of them do.
Which spigot should I use for the test?
The outdoor hose bib nearest where the main water line enters your home. That gives you the reading closest to what the street is delivering, before the water runs through the rest of the house.
My reading changes during the day. Is that normal?
Some change is normal — demand on the street main rises in the morning and evening. A swing of a few PSI is nothing to worry about. A swing of 20 PSI or more, or pressure that drops every time a second fixture runs, points to a restriction inside your home.
The gauge reads zero. What does that mean?
The main is off, or the bib is behind a closed valve. Check that the main shutoff valve is fully open and try another bib. If every bib reads zero while your neighbours have water, call us at (726) 465-7927.