Basements and cellars
A cellar sump pump was never switched on. Why is a dry pit today not proof the pump runs?
A dry pit shows the sump was empty on the day, not that the pump runs. The surveyor did not switch it on, did not raise the float and did not time a discharge. A cellar can look dry because the weather was quiet, because someone emptied it, or because groundwater was low. The power supply, the non-return valve and the outlet were not proved by an empty hole. A government flood-risk check is a separate product and was not this inspection. The report records a pump that was not operated. It has not decided the pump will cope when the pit fills.
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?
Sump pumps are meant to start when water lifts a float or a sensor. In a dry pit that switch never moves. A seized pump, a tripped supply, a stuck float or a blocked discharge can all stay hidden until water arrives. The survey did not invent a flow to watch. Seeing the pump body over a dry base is a visual note. It is not a commissioning test, and it is not a measurement of flood depth. Dry today is a snapshot of the chamber only.
Ask the solicitor whether any flood-risk search, basement warranty or pump service note is in the pack, and keep those papers separate from this report. The survey has not certified the pump and has not said the cellar will stay dry. If you need to know that it runs, someone equipped to do so can demonstrate it with water in the pit. This visit did not. Tell a lender only what was seen: a pump present, not operated, in a pit that happened to be empty.
What should you ask your surveyor?
- Is the pump plugged in, and was any isolation switch left off?
- Where does the discharge pipe go, and was the outlet actually seen?
- Does the report mention staining above today's dry base that would show earlier water?
What are the typical next steps?
- Treat the dry pit as a snapshot, not as a pump test.
- Ask the seller for any service note or when the pump last ran.
- If the cellar matters to you, have the pump demonstrated with water in the pit.
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 severe flood-map result mean this pump has failed?
No. A flood map is a separate product from this visit. It does not switch a cellar pump or inspect the pit, and the survey did not measure flood depth against any map. A dry day and an unfavourable map can both be true. Neither one proves the pump runs.
Should the pump be left switched off so the pit stays as dry as it was?
No. Leaving it isolated would hide the test you still need, and a cellar that fills with the pump off is a worse outcome. The survey did not operate the unit and does not tell you to alter the electrics. A pump specialist can demonstrate the float when you are ready to see water move.