about 15 yrs ago i was at a place in texas called lake of the pines,they couldnt use lateral lines because someone somewhere was using the lake water for drinking,so this guy had a septic that had a lawn sprinkler system made with it,he had to put i think he said clorine in the tank every so often and the sprinkler worked automatically when the level got so high,the water that came out of the sprinkler was pretty clean and clear,nothing drained into the lake,his grass growed good