Drainage and septic tanks
The house was a takeaway and a grease trap is still there. What has the survey not done?
It has not opened the trap as a service, has not proved what it still connects to, and has not camera-surveyed the drain. A grease trap left from a commercial kitchen is a piece of equipment. Grease in it is not, by itself, a collapsed sewer.
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?
Former shops and takeaways keep under-sink traps, floor gullies and large interceptors long after the fryers have gone. The surveyor can see a metal box, a cover in the floor, or a cupboard that smells. They do not dip the trap or jet the run on a home survey. Approved Document H is guidance for drainage when building work is done. It does not empty this trap, and it does not issue a camera grade. Do not invent one. A domestic buyer needs to know whether the trap is still on the live waste, whether it is redundant, and whether it leaks. The glance does not settle that.
Ask the seller what the trap still serves and for any cleaning record. A record is not a CCTV film. If the kitchen now discharges through the trap, a drainage firm can say whether it should stay, be cleaned, or be taken out of the run. Taking it out is not always an improvement. Do not tell a contractor to smash it out because the house is no longer a shop. Also do not write “collapsed sewer” because the lid is greasy. Collapse is what a camera or an opened pipe shows. This survey showed a trap from an earlier use. Keep that sentence tight.
What should you ask your surveyor?
- Where is the trap, and did you open it?
- Can you see whether today’s sink still discharges through it?
- Are you keeping grease separate from a claim that the sewer has collapsed?
What are the typical next steps?
- Do not empty the trap on a viewing.
- Ask what it still connects to before anyone removes it.
- If a camera is commissioned, ask them to start from this trap rather than from a guess about the street.
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 domestic sink mean the trap can be ignored?
No. It may still be on the pipe. The survey has not proved it is bypassed.
Is grease in a trap the same note as fat poured into a gulley outside?
No. One is a fitting in the building. The other is a discharge you might see in the yard. Name which one was seen.