Why is water discolored when they’re working on the lines but not normally?



From time to time, we get notified that the town is flushing the lines and water may be discolored until they’re done, and to run the water for 15 minutes. Why isn’t the water always discolored and what causes the discolored water?

In: Chemistry

You can replicate this effect at home. Just pick a faucet that you don’t need daily, and then don’t use it for a few months. When you first run it, you’ll have that same “rusty” water.

There is always a certain amount of rust and sediments in the water lines. But your normally functioning water system is a relatively stable and smooth flowing system. When they open up those huge lines to flush out fire hydrants though, you disturb that system quite a bit. The huge increase in water flow stirs up that sediment that normally happily sets at the bottom of your line, filling the water system with rust and debris.