How much flushing can be done

Maybe you can help shed some light on this phenomena?

We moved to Umina from Sydney three years ago.

Over those three years pretty much regularly we get brown water, usually on weekends.

If we do remember to call the water people on the following Monday, we get the standard "Oh yeah, flushing the pipes".

How much flushing can be done in three years?

Why should we have to pay for this disgusting water?

Dave Holmes Umina Beach