[monkeynotes]

This isn't entirely true. Rural properties have septic tanks that are maintenance free for years at a time. The waste is digested by bacteria in the tank and effluents runs off into a septic field. The tank is pumped out only when there is a substantial amount of undigested sludge filling the tank.

[frosted-flakes]

Depending pn usage, septic tanks can sometimes go 20 years before being pumped. My house has heavy usage (lots of people), so it gets pumped every 2 years or so. It could maybe go longer, but it's not worth risking it getting over-filled.