Electrics and gas
A boiler condensate pipe runs into a rainwater gulley outside. What freeze risk on that pipe was not tested in summer?
The freeze risk that was not tested is the chance this external condensate pipe blocks with ice in cold weather. The pipe was seen running into a rainwater gulley. A summer visit can record that route. It cannot show whether the pipe freezes, whether the gulley connection leaves a length of pipe in the cold, or whether the boiler would stop if the outlet blocked. No winter trial was done. The survey has not cleared the pipe for freezing.
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?
Boiler condensate is water the appliance must get rid of. An outside run to a rainwater gulley is exposed to cold in a way an internal waste is not. Ice in that pipe can back up. The surveyor saw the pipe and the gulley in warm conditions, or at least not under a freeze. They did not chill the pipe and they did not watch a thaw. Describing the gulley is not a test of that risk.
Ask a Gas Safe registered engineer to comment on the external condensate route, including how exposed it is, if you need that judgement before you rely on the boiler. Ask the seller for the boiler service record and give it to your solicitor. The home survey has not serviced the boiler and has not tested the freeze behaviour. Do not read a summer photograph of a gulley as a winter result.
What should you ask your surveyor?
- How much of the condensate pipe runs outside before it reaches the gulley?
- Did you see any insulation or trap on that outside length, or none?
- Have you recorded that freeze behaviour was not tested?
What are the typical next steps?
- Treat the gulley note as a route seen, not as a freeze test.
- Ask a Gas Safe registered engineer about the external condensate pipe.
- Request the boiler service record through the solicitor.
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 gulley was running clear, is freezing ruled out?
No. A clear gulley on the day of the visit shows water could leave then. It does not show what happens if the outside pipe ices up later. The survey did not test that freeze risk. Winter ice is a different event from a clear gulley on the day.
Is condensate the same finding as a leaking rainwater pipe?
No. Condensate comes from the boiler, and the rainwater gulley takes roof water. They meet at this outlet. A stain or a drip there is not automatically a failed gutter, and the survey did not test either system under freeze conditions.