Drainage and septic tanks
The tank has no outlet and the survey calls it a cesspool. Has anyone proved how often it is emptied?
Nobody on this visit has proved how often it is emptied. The tank has no outlet, and the survey calls it a cesspool because a cesspool holds sewage and is emptied, unlike a septic tank or a treatment plant, which are different and have an outflow. Calling it a cesspool from what was seen is a description, not an emptying record. The survey did not see a log, an invoice or a tanker. Frequency stays unknown. The survey only records what was seen.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
A cesspool is a sealed holding tank. With no outlet found, sewage stays in it until someone pumps it out. How often that happens depends on the household and the tank. Do not invent an interval from the size you think you saw. A septic tank would normally show an outlet to a drainage field. A treatment plant would normally show a powered process and a discharge. Those were not what the no-outlet tank showed. The name fits the observation. The calendar does not.
Ask the solicitor for emptying invoices or a contract with a tanker firm, and keep those papers outside the survey. A drainage firm can confirm the tank type if the cover is lifted properly on a later visit. Tell a lender the survey found no outlet, calls the tank a cesspool, and has no emptying frequency. Do not guess a routine. Until records appear, you do not know whether the tank is managed or already close to overflowing between visits that were never shown.
What should you ask your surveyor?
- Has an emptying interval been proved from records?
- Why does no outlet point to a cesspool rather than a septic tank?
- Did the survey see a tanker visit or only the tank?
What are the typical next steps?
- Treat emptying frequency as unknown.
- Ask the solicitor for tanker invoices or a service contract.
- Do not invent an emptying interval from the tank's appearance.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
How does a cesspool differ from the other tanks people confuse with it?
A cesspool holds sewage and is emptied. A septic tank and a treatment plant are different: they are meant to discharge onward, and a treatment plant is not the same unit as a septic tank. The survey saw no outlet and used the cesspool description. It only records what was seen. It has not proved how often any of them would be emptied.
Can the survey invent how often the tanker comes from the tank size?
No. Frequency was not in any record the survey saw, and size on its own was not turned into a timetable. Inventing an interval would pretend a measurement and a household pattern that were not taken. Ask for invoices. Until they arrive, say the cesspool's emptying record is missing. The survey has not filled that blank.