Drainage and septic tanks
Do permeable paving, together with a silted joint, count as evidence on water the hardstanding no longer takes, or only as a note of what was visible?
No. Permeable paving together with a silted joint is only a note of what was visible. It is not evidence that the hardstanding no longer takes water. Permeable paving is meant to let water through open joints or voids. Silt in a joint can reduce that, but the survey did not run water, did not test infiltration, and has not decided the paving has failed. The silt was seen. The performance was not. Do not promote a dirty joint into a drainage result the visit never produced.
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?
Permeable blocks rely on the gaps between them staying open down into a prepared base. Silt, moss and fines close those gaps from the top, so water may start to run across the surface instead of through it. That is the mechanism. It is also only a mechanism. A silted joint on the day shows dirt in the gap the surveyor could see. It does not show whether the base below is still open, blocked or even present. The hardstanding's capacity stays unmeasured.
If the paving matters to you, ask a drainage firm to test whether water still passes the joints and the base. The survey has not done that test and has not specified jetting or relaying. Tell the solicitor the silt is a visual note, not a proved failure. Sweeping silt would be maintenance, not a finding that the hardstanding has stopped working. Do not relay the drive on this sentence. Keep the paving type and the untested water path separate until someone actually tries the surface.
What should you ask your surveyor?
- How widespread was the silt: one joint, or most of the hardstanding?
- Was water standing on the surface, or was the joint only dirty?
- Could you see the base through the joint, or only the silt?
What are the typical next steps?
- Treat the silted joint as a visual note, not as a failed drainage test.
- Ask a drainage firm to test the paving if capacity matters to you.
- Tell the solicitor the hardstanding was not proved unable to take water.
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 permeable paving need to stay unsilted to be the right product?
The product is meant to pass water through the joints, so silt works against that design. The survey saw silt and did not test whether water still gets through. It has not decided the paving has failed, and it has not said the product was the wrong choice. Maintenance and failure are different. This note only establishes the dirt that was visible.
Will hosing the joints prove the drive still drains?
A hose can suggest what the surface does, but the survey did not do that, and a quick hose is not a proper infiltration test of the base. The silted joint remains a visual note. If you need a result, ask a drainage firm to test the paving. Do not treat a home experiment as the inspection that was missing.