Drainage and septic tanks
The extension appears to stand over the old drain run and no camera survey is attached. What bearing and what pipe condition are both untested?
Both are untested. The extension appears to stand over the old drain run, and no camera survey is attached, so neither the bearing nor the pipe condition has been demonstrated. The survey can record that the building seems to cross the line where a drain is thought to run. It has not exposed the foundation, load-tested the wall, or filmed the pipe. A home survey does not become a drainage investigation because two lines overlap on a sketch. The report leaves both the support under the extension and the state of the buried pipe undecided.
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?
An extension built across a drain can load the pipe, and a pipe can be cracked, displaced or simply not where the old plan showed. Neither problem is visible from a finished floor. Without a camera, the surveyor has not seen joints, fractures or standing water inside the run. Without opening the ground, they have not seen whether the wall bears on the pipe, beside it, or clear of it. Writing a clean bill over that gap would invent two results.
If this matters to the purchase, instruct a camera survey of the drain and, separately, ask someone competent about the bearing where the extension crosses it. Tell the solicitor both are outstanding, so a missing camera report is not treated as a pass. Do not ask the home survey to imply that the extension is sound because the rooms above looked level. Level finishes do not show a buried pipe. Keep the two untested questions named, rather than blended into a general worry about the extension.
What should you ask your surveyor?
- Where does the extension appear to cross the old drain, as you understand it?
- Was any camera survey or opening-up attached, or is both the pipe and the bearing untested?
- What should not be read as proof that the wall is clear of the pipe?
What are the typical next steps?
- Treat the pipe condition and the bearing as both untested.
- Do not infer a sound extension from the lack of a camera survey.
- Instruct a camera survey and a separate look at the bearing if you need both answered.
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 manhole is upstream of the extension, has the pipe under it been seen?
No. A manhole upstream shows the chamber you opened, not the length under the extension. Without a camera, that buried length and the way the wall bears on it are both still untested. The extension crossing stays unproved either way.
Does a new floor in the extension prove the drain was diverted?
No. A new floor is a finish. It does not show a diversion, a bridging detail, or the condition of the old pipe. The survey has not filmed the run and has not confirmed the bearing. Both questions stay open.