Basements and cellars
The lightwell gulley appears to join a foul stack and no dye test was done. What connection has not been shown?
The connection from the lightwell gulley into the foul stack has not been shown. The gulley appears to join that stack, which is what the pipes look like. No dye test was done, so water from the gulley was not traced. The survey has recorded an appearance. It has not proved the connection, not proved a different connection, and not shown where the lightwell actually discharges. Appearance is the finding. The connection itself remains unshown.
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 lightwell gulley collects rain at a basement opening. A foul stack carries waste. If the gulley really joins the stack, rain is entering the foul system at that point. If it only looks that way, the rain may leave by another pipe hidden behind the wall. The difference is exactly what a dye test shows and what a glance does not. The survey did not put dye in the gulley and did not watch a chamber. No one should treat the word 'appears' as a proved misconnection.
Ask a drainage contractor for a dye test of the lightwell gulley if you need the connection proved. Tell the solicitor the survey has not shown it. Do not describe the stack as wrongly connected, or as innocent, on the look of the pipes alone. The report stopped at an appearance. The connection has not been shown, and the test that would show it was not done.
What should you ask your surveyor?
- Did the gulley only appear to join the foul stack?
- Was a dye test left undone?
- Have you left the actual connection unshown?
What are the typical next steps?
- Treat the join as an appearance, not as a proved connection.
- Do not tell the solicitor the misconnection is certain.
- Ask for a dye test if the lightwell outlet must be known.
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 stack is plastic and new, has the connection been remade correctly?
New plastic shows a material, not a route. No dye test was done, so the connection from the gulley to the stack has not been shown, however recent the pipe looks. The survey recorded an appearance. A fresh fitting does not replace the dye.
Does rain in the lightwell on the day prove the outlet?
Rain shows water arriving. It does not show which pipe takes it, and no dye was added. The gulley still only appears to join the foul stack. The connection has not been shown. Weather is not a test of the plumbing.