Water pressure gauge installed on a water tank outlet tee © Daniel FriedmanWater Pressure Gauge Installation Guide
How to measure house water pressure by installing a permanent or temporary pressure gauge

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How & where to install a water pressure gauge to measure house or building water pressure: this article describes installing a water pressure gauge, starting with the best locations for installing a water pressure gauge on building water supply systems. We give step by step instructions for installing a water pressure measuring or monitoring gauge, and we include several alternative ways to measure water pressure if no gauge is present.

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Where to Install the Water Pressure Gauge & How to Measure Water Pressure

Reader Question: how do I know if my pump and tank are properly adjusted to the right pressure?

Dynamic water pressure measurement (C) Daniel FriedmanGeoff Asked: I have bought a new Davey X50 water pump with a 40 liter tank but it has no pressure gauge. How should I know if it is working at the right pressure please? - 2/15/2014

[Click to enlarge any image]



You are quite right that without reading the water tank pressure or system water pressure it's not possible to know quite what the water system is doing.

Temporary Measures of Water "Pressure"

You would have a clue that things are not right if you observe the water pump SHORT CYCLING,

or if water pressure at the fixtures appears subjectively weak (WELL WATER PRESSURE DIAGNOSIS) when you simply observe water flow at a faucet (my photo at left).

Even without installing a water pressure gauge permanently on the pump or tank or tank tee, you can of course measure water pressure using an ordinary tire-pressure gauge - if there is a schrader valve on the water pressure tank.

Depending on where this valve is mounted it may be sensing air pressure (at the top or upper portion of a water pressure tank) or it may be sensing water pressure (if the valve is mounted on a water pipe or on the water tank tee fitting). At below left we show a close-up of an air valve or pressure testing point on the tank tee at the bottom of a water tank. And at below right we show a nice tire pressure gauge in use measuring water pressure at one of these fittings.

Water tank air valve - shrader valve - is a location for measuring system pressure (C) Daniel Friedman Accurate dial gauge (C) Daniel Friedman

Water pressure test gauge on a hose bibb (C) Daniel FriedmanYou can also buy or make a simple water pressure test gauge that combines a water pressure gauge with a garden hose female fitting that lets you install the pressure gauge on a clothes washer hook-up in the home, at a laundry sink, or at an outdoor garden hose fitting connection (photo at left).

Watch out: many people confuse water pressure and water flow.

Someone may complain of poor water flow at a fixture (not many liters per minute of water are delivered) by calling that "water pressure" - which makes some sense in that a low flow rate means the water doesn't strike you very hard in the shower.

For more explanation see WATER PRESSURE MEASUREMENT


Install a Permanently-Mounted Water Pressure Gauge

But reading actual water pressure is such important and easy diagnostic tool for both private well and pump systems and also for MUNICIPAL WATER PRESSURE DIAGNOSIS too that installing a permanently-mounted pressure gauge is a good idea. If your water supply system has no water pressure gauge installed, adding one is the best bet. Water pressure gauges are not expensive.

Typically around $10. U.S. For best accuracy buy a pressure gauge whose range covers your pump operating range but not much higher.

Photograph of a water pressure tank air valveFor example a pressure gauge that displays pressures between 0 psi and 100 psi is a good match for a home water system that typically operates in the 20 to 70 psi range. You'll be able to read water pressure more accurately than if you installed a 0-500 psi gauge whose scale will leave you peering always at just the scale's low end.


Where to Mount the Water Pressure Gauge

In our photograph at left you'll see the most common location for water pressure gauges on a private pump and well system - at a tank tee fitting at the water tank outlet. The tank tee includes a tapping intended to accept a 1/8" or 1/4" NPT threaded water pressure gauge.

Other water pressure gauge tappings may be present such as on the pressure tank itself on its top or side, or even on the water pump housing. Because vibration of the pump can jiggle the tank gauge needle making it hard to read, I prefer to see the pressure gauge mounted on the tank or on a tank tee rather than on the pump itself.

For municipal water supply systems it's common to install the water pressure gauge in line on a fitting close to the water pressure regulator, on the house-side of the regulator - photo below right. At below right we show a water pressure gauge installed at a water pressure booster pump outlet tee.

Water pressure gauge mounted at a water pressure regulator - municipal supply (C) Daniel Friedman Water pressure booster pump closeup (C) Daniel Friedman

How to Install a New Water Pressure Indicator Gauge on a Water Tank or Pump

Watch out: before opening plumbing pipes or fittings to install a pressure gauge at an existing threaded tapping, turn off water equipment electrical power and remove pressure from the system. The well pump is turned off, pressure is drained from the system (you do not have to let all of the water out of the tank, just be prepared for a little spillage).

  • Buy a suitable water pressure gauge (discussed above) and prepare the new gauge for installation: the new water pressure gauge is prepared for installation (make sure the gauge bottom threads match those of the old unit being replaced as diameters vary from 1/4" to 1/2"). Pressure gauges are available at building supply stores, hardware stores, plumbing suppliers, and of course online.

Water pressure gauge mounted directly on a water pump (C) Daniel Friedman

  • Decide where the water pressure gauge will be installed (see the preceding discussion).

    If there is no removable plug and tapped fitting where you want to install the pressure gauge, look around for a pre-tapped, plugged suitable alternative: look at the pressure tank, the tank outlet tee and for pump and well systems whose pump is above ground, look for a pressure gauge tapping right on the pump itself.

    Our photo at left hows a water pressure gauge mounted directly into the cast-iron housing of a water pump - in this case a jet pump. This location was used because there was no tank tee fitting on the water tank.

    If there is no suitable existing threaded tapping to accept the pressure gauge some plumbing work to install one will be needed; ideally we install a tank tee fitting at the water pressure tank outlet; inline fittings on water piping at a suitable location are acceptable and may be easier to install.

    You may need to install a pipe tee that includes a suitably-sized tapping (1/4" or 1/8") in a position to allow you to connect the pressure gauge (below left), or you may be able to cut an existing copper water supply pipe just downstream (on the house side) of the water pressure tank to install a SharkBite™ quick-install tee that already contains a pressure gauge such as that shown in the photo at below right.

Water pressure gauge on pipe tee (C) Daniel Friedman SharkBite water pressure quick-install gauge

  • Turn off power to the water pump and drain most or all water pressure from the system.

    For municipal water supply systems turn off the main water supply valve.
  • Also close the valve between the water pressure tank and the building supply piping. This will prevent water in the building supply pipes from draining backwards down through the system and out at the valve mount point during installation.
  • Have at hand the new water pressure gauge of the proper pressure sensing range - and be sure that the pipe thread diameter of the gauge mounting base is the same as that on the old gauge so that you won't also need an adapter to mount the new gauge in the old position.
  • Prepare the new pressure gauge mounting threads by wrapping with teflon tape or applying pipe joint sealing compound - keep the compound away from the opening at the bottom of the gauge through which water passes, or you may clog your new gauge early.

    We put our teflon tape or pipe dope on the new gauge threads before trying to remove the threaded gauge fitting plug. Then the 18" or 1/4" plug (or the old gauge if this is a replacement operation) is removed by using a wrench on the plug )or on the brass fitting at the bottom of the old pressure gauge if one is present).

    Watch out: if you use pipe dope or thread sealant compound instead of teflon tape, take care not to get a blob of pipe dope on the little opening in the center of the bottom of the pressure gauge brass mounting fitting - crud in that opening can clog it, causing the gauge to fail to read pressure accurately - or at all.
Water pressure gauge installed on a water tank air volume control © Daniel Friedman
  • Remove the 1/4" or 1/8" tapping plug at the location where the gauge is to be installed.

    Watch out: if water comes squirting all over the place you forgot to remove water pressure from the system. Don't panic, just screw the plug back in - it does not have to be tight, and a little dripping is OK (you've got a pan under the fitting, right?). Now be sure the pump is off, or for municipal water supply systems be sure you've turned water off at the main water valve.

    At left we show a pressure gauge mounted right on the air volume control of a bladderless water pressure tank.

    Watch out: if no one has touched the main water valve for a long time it may be difficult to turn. Don't force it - if you break the valve you could indeed flood the building. If you can't close the valve (you're turning it the correct direction - clockwise - right?) with moderate force it may be smart to give up and call a professional plumber.
  • Calmly screw in the new pressure gauge even if water is flowing out of the gauge mounting hole. Screw in the new gauge first by hand to be sure that you are threading it correctly don't "cross" thread the gauge into the mounting opening or it will leak. Finish tightening the water pressure gauge in place with a wrench around the brass gauge base. Tighten the new gauge carefully in position with a wrench on the gauge bottom brass fitting. Do not over-tighten, but screw in the new gauge until there is no water leakage.

    Watch out: don't use the pressure gauge body to try to turn the gauge into its tapping - you'll probably break the gauge. Use a wrench on the brass or bronze fitting at the base of the gauge - intended for that purpose.
  • Screw in the new gauge first by hand, finishing it with a wrench around the brass gauge base.
  • Restore the water supply source: turn on power or open main water valves
    • For water pump and well systems or booster pump systems: Turn pump electrical power back on. Open the valve between the water pump/tank system and the building water supply piping.
    • For municipal water supply systems open the main water supply valve.

      We like to open the main water valve fully (counter-clockwise) then back it off from full-open about 1/4 turn - under the fantasy that leaving this play in the valve may allow us to turn it back and forth and get it turning again ten years from now when it's stuck again.
  • Check the water pressure gauge for leaks & for pressure reading: observe new gauge pressure indications for normal operation and watch out for leaks.

    If you see leaks at the threaded gauge mount it may not be tight enough, or you didn't use enough teflon tape. Try gently turning the gauge in (clockwise) to tighten it but DON'T FORCE the gauge too tightly. Instead, if leaks continue, start over with another two more turns of teflon pipe tape around the threaded gauge base - increasing the pipe tape beyond what you tried the first time.

    If you are confident that the new pressure gauge is properly installed and in good condition but water pressures are incorrect for a private well and pump system or for a municipal water supply booster pump system then the problem may be at the water pump pressure control itself.

Continue reading at WATER PRESSURE GAUGE


To buy or make your own portable water pressure measurement gauge, see WATER PRESSURE MEASUREMENT.

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WATER PRESSURE GAUGE INSTALLATION at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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