- System
- Sealed cesspool / cesspit
- Function
- Hold sewage for removal
- Important difference
- No intended effluent outlet to a drainage field
- Useful records
- Capacity, level alarm and removal history
How a sealed cesspool works
A sealed cesspool, also called a cesspit, stores sewage for removal. Unlike a septic tank, it is not intended to pass effluent to a drainage field or other downstream treatment stage.
The distinction matters because maintenance patterns are different. Informal names such as ‘septic pit’ do not show whether a tank is sealed or has an outlet, so installation records, plans or a competent inspection may be needed to confirm the system type.
Capacity and emptying frequency
The time between emptying visits depends on usable tank capacity and the amount of wastewater entering it. Occupancy, commercial use and additional water ingress can all change the filling rate, so a fixed interval taken from another property is not a reliable basis for the schedule.
Collection dates and removed volumes provide a useful baseline. If the interval shortens unexpectedly, increased inflow, water ingress or another change to the system may need investigation.
Levels, alarms and access
Where a level alarm is fitted, it should be maintained in accordance with the installed system’s instructions. Its warning point and meaning depend on the system, and it should not be disabled or treated as an overflow control.
Safe access for emptying depends on the tank cover, surrounding ground and a suitable tanker and hose route. Tank openings and interiors present serious hazards and are not places for informal entry or inspection.
Changes in filling rate
A cesspool that needs emptying much more often than its established pattern deserves attention. The cause may be a change in occupancy or water use, but unexpected inflow can also come from drainage defects or groundwater entering the system. Routine emptying removes the stored sewage; it does not diagnose a leak, damaged structure or unusual inflow.