Water System Leak Gauge

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This gauge was built to verify whether my water pipes were leaking and running the well dry. It won't pinpoint a leak, but it will show the actual volume of loss.
Bad Coon
~as free as it gets~

  • why it's useful
  • how it works
  • drawing, parts list & prices
  • the hippy version
  • how to use it
  • the math

    pressure tester Why it's useful

    The standard leak check is to simply pressurize the system and watch for pressure dropping on a gauge dial like the one shown on the right. This is required for contractors because everything should be new, so any drop at all means poor work. . . Howevah:

    If your system was installed by unknown yahoos 30 years ago, and today's test indicates a leak, you might wonder if it's worth digging up the property for $1000+ to replace a badly glued fitting when you don't know the leaks volume. A standard test won't tell that because of the thing that makes pressure tanks work: that large systems can drop more slowly than small systems with the same size leak because pipes and hoses expand under pressure and they sometimes contain air bubbles. Water doesn't compress much but bubbles do. With those two factors, the same size leak will loose pressure more slowly in a large system than in a small system causing the leak to appear to be smaller. The gizmo described below maintains normal pressure in the system so there are no variations in volume.

    How it works:

    The gauge is basically a bubble in a tube connected between the house water system and a regulated source of compressed air. Both sides of the bubble are set to the same (house) pressure. Then the water system is turned off at the main valve to the house. If a leak exists, the pressure drops on the house side so the bubble is pushed by the compressed air, relative to the rate of the leak. A count-up kitchen timer or stopwatch is started when the house valve is closed, to time the duration. The volume of the loss is equal to the volume of the tube that the bubble moved through for the measured time.
  • If you're not into making stuff that sprays water, it's possible to buy, rent, or borrow a portable water meter for a few bucks. Ask your local water utility, hardware rent-all, or building dept.

    Parts list and Drawing

    These are new parts prices (rounded off) that I looked up as of April 2014, but it can be made from garage sale scraps for a lot less.

    The Hippy Version : has the same general loop shaped like "LA" with 2 valves, but is made from drip irrigation parts and costs 80% less, even cheaper ( but not nearly as easy to use) as the above portable water meter.

    It doesn't use a pressure regulator, dial gauges, bicycle pump air fitting, copper tube fittings, or brass hose barbs w/ stainless clamps. It relies instead on a high loop (the top of the "A") to contain enough air when pressurized to form a bubble without adding one (w/ the bicycle pump). The ruler is moved to locate on the edge of the bubble and sticks to the tube w/ tape. Instead of a pressure regulator, an obsolete style propane bottle (or something, maybe a hose from a neighbors house) could be used to pressurize the system. An upside down propane bottle is filled from empty with water from the same system, the air thus compressed like a well pressure tank will match the house pressure. Works the same way as the one in the drawing and in the procedure below (next).