A typical home has either a 3/4” or 1” main water service line entering the home before the water heater(s), however with newer and larger homes with greater demands on water usage or multiple water heaters, large shower or bathing systems larger service lines of different sizes are not uncommon. Condos and apartments often have 1/2" pipes.


  1. „Grab a piece of string about 6"(152mm) long.
  2. „Find the location of your water supply pipe (either in your basement, garage, utility area or outside). You’ll know it’s your main supply pipe when you see a shut off valve that shuts off all the water to your home.
  3. „Strip away any insulation so you can get at the pipe and wrap the string around it. „
  4. Measure how many inches of string it takes to go around the pipe once. This is the circumference of the pipe.
  5. Using the circumference we can calculate the diameter of the pipe.
  6. Based on the string length use the table provided to find your pipe size:
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