Drainage and septic tanks
The washing machine wastes into a surface-water gully. Has a dye test proved a misconnection?
No. A dye test has not proved a misconnection. The washing machine wastes into a surface-water gully, which is an arrangement that can send foul water toward a rainwater system, but the survey did not put dye through the machine, did not film the drain, and did not trace where that gully discharges. A hose sitting in a gully is not a test of the pipe beyond it. The report notes the connection as found. It has not decided the gully is misconnected, or correctly linked to a foul drain.
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?
Misconnection means foul waste leaving by a route meant for rain, or the reverse. The harm depends on where the gully actually goes: a combined drain, a surface-water sewer, or a soakaway in the garden. None of those destinations was shown on this visit. The surveyor is not claiming a drainage test that did not happen. Smell, staining or a wet gully would still only be clues. They were not turned into a trace.
If you need the route proved, instruct a drainage firm to dye-test or film it, and give that result to your solicitor as a new document. Tell a lender no dye test was done, so a misconnection is not a finding and a correct connection is not a finding either. Do not let the seller's assurance stand in for dye. The survey's sentence is only that the machine wastes into that gully.
What should you ask your surveyor?
- Was dye put through the washing machine on this visit?
- Has the gully been traced to a foul drain or a rainwater drain?
- Is the hose position being reported as a proved misconnection?
What are the typical next steps?
- Treat a misconnection as unproved.
- Instruct a drainage firm if you need a dye test or a film.
- Do not tell a lender the drain has failed or passed.
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 surface-water gully always lead to a river or a soakaway?
No. The name describes the fitting, not the destination the survey proved. Some gullies join a combined system and some do not. This visit did not trace the outlet and did not use dye. Where this gully goes is still unknown. Do not invent the downstream pipe from the words on the grate.
Can the machine be moved to a different waste as part of the survey?
No. Re-plumbing the machine is works, not an inspection. The survey recorded where it wastes now and did not test that route. Any change would be a later job with its own proof. Until then the note stands: the machine discharges to a surface-water gully, and no dye test was done.