Drainage and septic tanks
A grease trap remains from when the room was a cafe. Has it been proved still connected to the foul drain?
No. The grease trap has not been proved still connected to the foul drain. It remains from when the room was a cafe, which explains why it is there. The survey saw the trap. It did not dye-test it or camera the foul drain. The trap could be connected, capped or abandoned. None of those was proved. The report records a leftover fitting. A live connection to the foul drain is unproved.
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 grease trap once sat on a waste pipe so fat was held back from the drain. When the room stopped being a cafe, the trap may have stayed in the run or been left as a dead box. A lid does not show where the outlet goes. Without a trace, the survey cannot say foul water still passes through it. The cafe past is history. It is not a test of the pipe.
Ask the solicitor whether any note covers drainage changes when the cafe use ended. A drainage contractor can trace whether the trap still joins the foul drain. The survey has not done that trace and has not called the trap blocked or clear. Do not tell a lender the foul system was proved through this chamber. Opening it later would be new work, not a rereading of this report.
What should you ask your surveyor?
- Was any outlet from the trap visible?
- Is there a plan showing the trap on the foul drain?
- What test would show a live connection rather than a dead box?
What are the typical next steps?
- Tell the solicitor the trap was seen and not proved connected.
- Ask for any note of drainage changes after the cafe use.
- Have a contractor trace the outlet before you rely on the trap.
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
Is a grease trap a kind of septic tank?
No. A grease trap is a small chamber on a waste pipe, meant to catch fat. A septic tank is a buried system that settles sewage for a property. The survey has not called the trap a septic tank and has not proved it still joins the foul drain. The cafe history explains the fitting. It does not change what the fitting is.
Does the old cafe use mean the foul drain was rebuilt?
Not on this evidence. The survey saw a remaining trap and did not prove a connection, a bypass or a rebuilt drain. The change of use may have included drainage work, and it may not. That is a question for the solicitor and the papers. The visit has not shown the foul drain was altered.