Looking around at the local home improvement center for a water pressure gauge, and all they seem to have is a gauge with 3/4" FGHT (Female Garden Hose Thread). Of course I could get a bunch of adapters (3/4" MGHT x 3/4" MPT -> 3/4" FPT x 1/2" FPT -> 1/2" MPT x 1/4" FPT), but I'd rather not.

The only other gauge I can find, is a 1/4" MPT gauge in the air compressor section of the store. Specifically a Husky 2 in. Heavy-Duty Side-Mount Gauge.

Husky 2 in. Heavy-Duty Side-Mount Gauge

This gauge is exactly what I'm looking for, except that it's designed to work with compressed air.

Would there be a problem using this gauge designed for compressed air, to measure water pressure?

  • I think pressure is pressure but air gauge is not designed for contact with water so it would likely have a limited life. – paparazzo Sep 10 '15 at 17:44
  • Doubt it. Gases are compressible. Water is pretty much not compressible. At best, that'd throw off calibration. At worst, it'd ruin the gauge. – Wayfaring Stranger Sep 10 '15 at 18:52
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    It looks like the Watts water pressure gauge has a 1/4" NPT screwed into a 3/4" FGHT adapter. Just need to unscrew the adapter to get the pipe thread. – diceless Sep 10 '15 at 22:25

Pressure gauges commonly use a Bourdon tube. Bourdon tubes are a coiled metal tube and as the pressure increases, it forces the coil straight which then moves the needle. (think blowing a party horn, which causes it to unroll) The type of fluid (water/air) makes no difference to the tube, only the pressure exerted against the tube does. And since most of the tubes are made from bronze, copper or stainless water will not corrode it any faster than moist air from the compressor.

In all said, the air compressor gauge will most likely work without any issues.

But if you really want to get a water gauge, go to a pool supply store. They have pressure gauges for filters that are designed for water and use a 1/4 npt. They also have a nifty little ring on the outside where you can mark your normal pressure so it is easy to see if your pressure is low or high.

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    @Tester101 - changed the answer to take into account no other store existing. – diceless Sep 10 '15 at 22:20
  • Excellent answer, but it is "Bourdon" tube. – R Drast Sep 11 '15 at 17:04
  • @RDrast thanks for the typo heads up. Must of had whisky on my mind and my spell checker changing Bourdon to Bourbon. – diceless Sep 11 '15 at 18:03

Pressure is pressure regardless if it's from water or air. Compressed gas cylinders are tested with water. So you can use any type of gauge. The gauges you find at the pool store aren't anything special. They're just cheap generic pressure gauges.

If you are going to use a gauge with water where you might encounter cold temperatures, I would suggest getting an oil filled gauge. On a normal gauge, if moisture gets in the gauge and freezes, you can probably mess it up or have it loose calibration. The oil will prevent any ice crystals from getting anywhere near the internal mechanism.

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