Dumping grey water in large quantities (500 gallons).

I have a friend who has wintered near Yuma, AZ. on BLM land. He was required to haul all wastewater to an approved dump station, which pumped it to a collection system/treatment plant. Discharging anything to the land, water, storm, or sanitary sewer requires an approved permit. Close encounters with EPA and the US Justice Department are quite painful and expensive.