Drainage and septic tanks
The gully grate sits proud of the new paving, so water runs past it. Is that a failed underground drain, or a level the paving has left wrong?
The gully grate sitting proud of the new paving is a level the paving has left wrong, not proof that the underground drain has failed. Water runs past the grate because the surround is lower than the grating. That fault is visible at the surface. It does not describe the buried pipe, a collapse or a blockage further along. Noticing a proud grate is not a survey of the drain beneath it.
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?
New paving is often finished high or low against a gully that was set to an older yard. Here the grate stands above the slabs, so water takes the path around it. The chamber, the bore and the outfall were not judged by that observation. Whether the underground drain is clear or blocked would need its own inspection, and this comment is not that inspection.
Resetting the paving or the gully is the direct question from what was seen. Do not jump from a proud grate to a replaced drain. Silt, a displaced joint or roots would be separate notes if they were recorded. A camera is a further instruction, not part of this visit unless it was agreed. Keep the surface level and the buried drain apart.
What should you ask your surveyor?
- Does the grate stand above the paving so that water misses it?
- Did you open the gully or a chamber, or did you only see the surface level?
- Are you calling this a paving level rather than a failed underground drain?
What are the typical next steps?
- Correct the levels so surface water can enter the gully.
- Do not replace the buried drain because the grate sits proud of the paving.
- Keep any worry about the underground run as its own investigation.
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 water ponds beside the gully, has the drain collapsed?
Not from the height of the grate. Ponding fits water that cannot enter a proud gully. The buried pipe was not surveyed by that surface observation.
Is relaying the paving the same job as surveying the drain?
No. The visible fault is the level around the grate. The underground run, if it needs to be seen, is a separate instruction.