Drainage and septic tanks
The only manhole is in the neighbour's garden and it was not lifted. What of the run under your lawn is unknown?
What is unknown is the run under your lawn. The only manhole is in the neighbour's garden, and it was not lifted, so the drain that would be seen from that chamber was not inspected. The survey has recorded the location and the closed cover. It has not seen the pipe under the lawn, its falls, its joints, or any blockage. Access sat next door. The length on your side of the boundary stays unknown.
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 manhole is the place a drain is opened and looked at. If the only one is on the neighbour's land and the cover stays down, there is no view along the pipe that crosses your lawn to reach it. Evenness of the grass does not describe the bore of the pipe. The surveyor could not lift a cover they did not open, and they should not guess the hidden run. A home survey does not include a drain test as standard.
Ask the solicitor how access to the neighbour's manhole can be arranged if you need that run inspected, and do not assume the survey has already seen it. Tell them the cover was not lifted. Instruct a drainage contractor only once access exists. Do not treat a tidy lawn as a clear drain. Keep any later camera report separate from this closed cover.
What should you ask your surveyor?
- Where is the only manhole, relative to the boundary?
- Why was that cover not lifted?
- What length under the lawn stays unseen?
What are the typical next steps?
- Ask the solicitor how access to the neighbour's manhole could be arranged.
- Do not treat the lawn as a clear drain.
- Instruct a drainage inspection only once that cover can be lifted.
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 lawn is even, is the pipe under it known?
No. An even lawn is the surface. The pipe under it was not seen, because the only manhole is in the neighbour's garden and was not lifted. Turf does not describe joints, falls, or blockages. The run stays unknown until that chamber, or another opening, is actually inspected.
Can this survey lift a cover that sits in the neighbour's garden?
Not on the day of this survey. The cover is on the neighbour's land and it was not lifted. The report cannot pretend it was. Access would be a later arrangement through the neighbour. Until then, the run under your lawn remains outside what was inspected.