Seller-side surveys
The seller already knows the drain blocks in heavy rain. What should they not do to that evidence before the buyer's survey?
They should not hide it, flush the signs away for the morning of the visit, or stay silent hoping the surveyor never asks. A home survey does not guarantee concealed drains, and a standard Level 1 or Level 2 inspection does not lift chamber covers. Hiding a blockage you already know about does not make the drain sound. Tell your solicitor the history so it can be disclosed. Do not dress the visit up as a test the surveyor did not do.
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?
Heavy rain that backs a drain up is a fact about the house. The surveyor may see staining, a slow gully or nothing at all if the day is dry and the covers stay down. Services comments are visual. They are not a water test and they are not a camera. If you spend the morning pouring cleaner down a gully so the chamber looks quiet, you have changed what can be seen. You have not changed the drain that blocks when the rain returns. No survey level guarantees concealed parts are sound, which cuts both ways: a clear look is not a certificate, and a hidden fault is not erased.
The practical step is to tell your solicitor what happens in heavy rain, and to let them advise what is said to the buyer. Do not instruct anyone to call the unseen run a rating 1. Rating 1 means no repair is currently needed on an element that was inspected, beyond normal maintenance. A drain you know blocks has not been given that clean bill by a visit that did not open it. Leaving covers in place is normal for those survey levels. Using that limit as cover for a known problem is the step to refuse.
What should you ask your surveyor?
- What do you already know about the drain in heavy rain?
- Will chamber covers be left in place on this inspection?
- Are you hoping a dry day will be described as a test?
What are the typical next steps?
- Tell your solicitor about the blockage you already know.
- Do not hide or temporarily clear the evidence for the visit.
- Do not describe an unopened drain as a rating 1.
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 a visual survey certify the drains?
No. Services are visual only and are not safety-tested. Covers stay down on a standard Level 1 or Level 2.
If the report is silent, has the drain passed?
No. Silence, or a cover that was not lifted, is not a pass. NI means not inspected.