How to flush your water pipes with compressed air

I replaced my water main and because some sediment got caught up in the line it got into my home plumbing. This messed up a lot of my valves, and required that I flush it out. We have high ferric iron in our well water too, so the lines had about 15 years of build-up in them. I wanted to do this before I installed a whole-house water filter, so we can have decent quality water finally. My wife’s greatest fantasy.

  1. Shut off main water supply
  2. Shut off water heater
  3. Close valves to all your water outlets, especially toilets, showers, washing machines, dishwasher (disturbed sediment may damage these)
  4. Open an exterior hydrant/spigot, place a bowl or bucket beneath to check progress
  5. If sediment is large, remove the hydrant/spigot’s valve so it’s a straight flow out
  6. Unhook the lines from the part of the water system furthest away from the spigot
  7. Blow <50psi air into the hole of the hot water supply line. Water will come out of the spigot and the cold supply line if you have it disconnected. Collect that water and put it down the drain.
  8. When water stops coming out, close all your valves (or hook the supply lines back up)
  9. Turn on the main water supply for a minute or so, a bunch of nasty crap will come out of the spigot. Once it’s clear turn it back off again and do the steps 6+ again with the cold water side. Repeat with both hot and cold again and again until the water comes out reasonably clear from the external spigot.
  10. Once satisfied, let your cold run out of the spigot and hot out of a sink that has it’s aerator removed. Let it run until the water is clear. This may take a while.

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