Basements and cellars

If the cellar sump was switched off, what could the survey say about whether it pumps?

Only what was visible while it was off. If the sump was not switched on, the survey could not see it pump, hear it run, or watch the water level fall. A pump, a float and a pipe on the floor are not a demonstration. The report should say the unit was off, not that the cellar drainage worked.

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 sump is there to lift water that reaches a cellar. Seeing the box does not show that the float switches, that the pump turns, or that the pipe actually leaves the building. Power may be isolated. The seller may have switched it off for the visit. An ordinary home survey does not turn equipment on as a trial and does not service plant. This is not a request for a test the inspection never included. It is a limit: off means not seen working. A high-water mark above the sump, or a stain the pump did not prevent, still belongs in the report.

Concealed pipework from the sump is not guaranteed. A RICS home survey will not have proved the outfall. Do not write 'sump present' in your own notes as 'cellar kept dry'. Ask the seller who services it and when it last ran, and treat the answer as hearsay unless you later see it run under a separate instruction. If the cellar was dry on the day and the pump was off, you still do not know what happens in a wet week. The survey should not fill that gap with a pass.

What should you ask your surveyor?

Was the sump switched off, isolated, or simply not operated?
Did you see a waterline or a stain the pump had not dealt with?
Are you limiting your comment to what was visible while it was off?

What are the typical next steps?

Do not read a pump standing in the corner as a pump that works.
Ask the seller for service information, and do not treat the reply as a test.
If you need to see it run, that is a further visit with permission. It was not this survey.

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

Does a dry sump pit mean there is no water problem?

No. A dry pit on a dry week, with the pump off, does not show the wet-week behaviour.

Is a battery backup part of what was checked?

No. The survey did not run a power-cut trial. A second box on the wall is only a second box until someone tests it.