Basements and cellars
The cellar sump float is stuck in the up position and the pump did not start. What flooding path is that pump there for, and what test was missed?
The pump is there for water that collects in the cellar sump, and the test that was missed is making it start. The float is stuck up, and the pump did not start. A sump takes water that reaches the lowest point, whether from the basement drainage or from seepage the system was built to lift. The survey has recorded a stuck float and a silent pump. It has not freed the float, not proved the pump runs, and not followed where that water would go if the sump overflows. The missed test is an operating test of the pump.
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?
Floats stick when they are jammed, scaled or left high by sludge. In the up position a float can look as if it is calling for the pump, while the pump does nothing. That is not a completed test. It is a failure to start on the day, from a float that would not move. The survey did not dismantle the pump or pour water to see it lift. The flooding path is the water the sump is meant to catch before it spreads across the cellar.
Ask a drainage contractor to free the float and to test the pump, including where the discharge goes. Tell the solicitor the cellar pump did not start. Do not describe the basement system as working. The survey saw the opposite of a successful test. Until the pump is shown to run, the sump is a hole with a stuck float, not a proved defence against flooding.
What should you ask your surveyor?
- Was the float stuck up, and did the pump fail to start?
- What water is that sump there to collect?
- Did you leave an operating test of the pump uncompleted?
What are the typical next steps?
- Treat the stuck float as a pump that was not shown to run.
- Ask a contractor to free the float and test the pump.
- Do not describe the cellar system as working.
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
If the sump was empty, is the pump unnecessary?
Empty on the day means no water was sitting there then. It does not mean water never arrives, and it does not mean the pump works. The float was stuck and the pump did not start. The test was missed. An empty pit is not a substitute for that test.
Does a new pump in the corner change the stuck float?
Only if it is the pump that was tested, and this one was not. A new casing can still have a float stuck up. The survey did not see it start. Replacement on paper is not a test. The flooding path the sump is there for remains unproved in operation.