Drainage and septic tanks
A washing-machine waste appears to run to a crate soakaway in the garden. Why is foul water into a soakaway not the same thing as a roof-water soakaway?
Foul water from a washing machine into a crate soakaway is not the same thing as a roof-water soakaway. The machine waste is dirty water from the house. A roof soakaway takes rain from gutters. Both can end in a crate in the garden, and they are still different discharges. The survey can record the waste pipe that appears to run that way. It has not tested the ground, traced every joint or accepted the connection. The note is a foul waste to a crate, not a rainwater system.
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?
Roof water is rain. A soakaway for it is a way of returning that rain to the ground away from the walls. A washing-machine waste carries detergent and dirt from clothes. Putting that into a crate in the garden is a foul discharge to the ground, even when the crate looks like the ones sold for rainwater. The survey has not dug the crate up, and an appearance of a pipe run is not a dye test. The distinction is the water, not the plastic crate.
A drainage specialist should confirm where the machine actually discharges, and the solicitor should not describe it as a rainwater soakaway in the papers. Rules about foul drainage are for that specialist and the authority, not a guess from the survey. Do not accept a note that the garden has a soakaway as if all soakaways were the same. This one, if the pipe is as it appears, is taking house waste.
What should you ask your surveyor?
- Which waste pipe appeared to run to the crate?
- Did you test the connection, or only see the route?
- Have you separated this from a roof-water soakaway?
What are the typical next steps?
- Call it a washing-machine waste to a crate, not a rainwater soakaway.
- Do not accept the connection just because a crate is in the garden.
- Have a drainage specialist confirm where the machine discharges.
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 same crate also takes a rain pipe, are the waters still different?
Yes. Rain and washing-machine waste can share a hole and remain different discharges. Adding roof water does not turn the foul waste into rainwater. The survey has not approved the shared crate. It has flagged a house waste that appears to reach it.
Is soapy washing water really foul water?
It is waste from the house, not rain from the roof. Soap does not make it roof water. The survey has not sampled it. The reason it is not a roof-water soakaway is the source of the pipe, which is the machine.