Flushing the hydrants? Interesting, I hadn't heard that. Well, I dunno. I think it's us, or something in the house. I noticed how yellow the water is on occasion though.
We're thinking maybe the water softener is shot. First you get good pressure, then it slowly dies away to about half.
If you flush a toilet, forget getting anything more than a dribble for about 5 minutes. It's very irritating
Since our WS doesn't have a by-pass it's not real easy to check, either.
When you're a homeowner, ain't it always something!