Hi Mark, I am on the Covington Water District near Kent WA. Reputed to be some of the best water in the sound area. Tastes better than any bottled water. Very low in TDSs. Very rarely any chlorine in the system. Started running RO to see any difference. Algae levels much lower, corals growing much faster. Phosphates lower now too and so reacter media lasts longer. Pain in the rear, but appears to be worth the effort. In some towns, absolutely vital.