Cesspits

Unlike a septic tank or treatment plant, a cesspit (or cesspool) doesn't treat wastewater at all — it simply stores it in a sealed, watertight chamber for later removal by tanker. That makes cesspits comparatively simple but expensive to run, since a typical household cesspit needs emptying every few weeks rather than the year or more you'd expect from a septic tank. They're usually chosen where ground conditions or a lack of space rule out a drainage field.