Drainage and septic tanks
The basement WC uses a pumped waste, and the survey did not switch the pump on. What remains unknown?
Not whether the pump runs, whether it lifts the waste, or where that waste discharges. The basement WC uses a pumped waste, and the survey did not switch the pump on, so those points remain unknown. The survey can record the unit it could see. It has not proved the float, any alarm, or the rising pipe. A pump is a machine. Looking at the box is not operating it. Ask a plumber to run the pump with the seller's agreement before you rely on the basement WC as a working closet.
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 basement WC sits below the drain, so the waste has to be lifted. The pump, its chamber and a small rising pipe are what a survey can note when they are visible. Not switching the pump on means nobody confirmed that it starts, stops, or delivers water to a stack. A dark alarm lamp is not a test. The rising pipe may leave the room at once, so the discharge point can stay unknown even when the box itself was seen and described.
Ask a plumber to operate the WC, watch the pump through a cycle, and trace the rising pipe while it is exposed. Do not pour water in as your own experiment, and do not jam the float. Tell them the survey left the pump untested, so a quiet basement is not mistaken for a pass. If there is an alarm or a backup supply, ask for that to be commented on separately. The open question is performance, not the label in the report.
What should you ask your surveyor?
- Did you see the pump itself, or only a basement WC described as pumped?
- How far was the rising pipe visible before it left the room?
- Was there an alarm or isolator that you noted but did not test?
What are the typical next steps?
- Treat the untested pump as an unknown, not as a working basement WC.
- Ask a plumber to run the pump and trace the visible rising pipe.
- Do not flood the pan yourself to see whether the pump starts.
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
Is this basement pump the same installation as a macerator in a loft?
No. Both are machines, but they are different fittings in different rooms. This pump was not switched on, so its own lifting performance remains unknown.
If the chamber looked dry, has the pump passed?
No. A dry chamber on one visit is not a test. The survey did not switch the pump on, so you still do not know that it lifts or where it sends the waste.