Drainage, surfaces and lawn
Soakaway problems: when a soakaway stops working
A soakaway is a stone-filled or crated pit that disperses rainwater into the subsoil. It fails when it silts up, the subsoil cannot absorb water (often heavy clay), or it is undersized, causing waterlogging, overflowing gullies and damp near the house. Fixing it usually means clearing, enlarging or relocating it, sometimes after a soil percolation test.
- Also known as
- soakaway failure, blocked soakaway, drainage pit problems
- Easily confused with
- a blocked drain, a high water table, general garden waterlogging
- How serious
- Low to moderate: a slow nuisance that can cause waterlogging and damp
- Typical cost
- Usually no cost for DIY control
How to identify soakaway problems
Signs of a failing soakaway are water backing up at the gully or downpipe it serves, a persistently wet or boggy patch over where the soakaway is buried, and slow draining after rain that used to clear quickly.
In severe cases water can pool near the house and contribute to damp. If a soakaway worked for years and then fails, silting is a likely cause; if it never worked well, the subsoil or sizing is probably wrong.
How serious is it?
Low to moderate: a slow nuisance that can cause waterlogging and damp
A struggling soakaway is usually a slow-developing nuisance rather than an emergency, but it can lead to garden waterlogging and, where water collects near the building, to damp.
Because soakaways depend on the ground absorbing water, a poorly performing one in clay soil may never work well, so the fix can mean a different drainage approach rather than just a repair. Soakaway design is also covered by building rules, so significant work should be done correctly.
How to fix it yourself
- Confirm the problem is the soakaway, not a blocked drain upstream, by checking gullies and chambers between the downpipe and the soakaway first.
- Clear silt and debris from the inspection point or the gully feeding the soakaway if accessible, since silting is a common cause of failure.
- Reduce the load reaching it where possible, for example by diverting some surface water elsewhere, as a short-term measure.
- Recognise the limits of DIY: digging up, enlarging or relocating a soakaway, and judging whether the subsoil can absorb water, is specialist work.
When to call a professional
- The soakaway is silted, undersized or in unsuitable clay soil and needs enlarging, relocating or replacing with another drainage solution.
- Water is pooling near the house, or you need a percolation test to design the right system.
Who to call
- A drainage specialist or groundworker to assess, clear, rebuild or relocate the soakaway.
- A drainage engineer where a percolation test or compliant soakaway design is needed.
Frequently asked questions
How do I know if my soakaway has failed?
Common signs are water backing up at the gully or downpipe it serves, a persistently boggy patch over the buried soakaway, and slow draining after rain that used to clear quickly. Pooling near the house is a more serious sign. Rule out a blocked drain upstream before blaming the soakaway.
Why has my soakaway stopped working?
If it worked for years then failed, it has probably silted up. If it never drained well, the subsoil may be heavy clay that cannot absorb water, or the soakaway may be too small. Soakaways rely on the ground soaking up water, so the soil type is often the deciding factor.
Can I fix a soakaway myself?
You can clear accessible silt and rule out upstream blockages, but digging up, enlarging or relocating a soakaway and judging whether the subsoil can absorb water is specialist work. A drainage specialist can carry out a percolation test and design a compliant replacement if needed.
Sources
Editor, HomesAndHedge
Oliver leads HomesAndHedge's editorial coverage of home and garden problems. He researches and writes the plain-English explainers on pests, invasive plants, damp and mould, drainage and wildlife, drawing on guidance from bodies such as the Property Care Association, the RHS and the NHS, and is clear about when a job needs a qualified professional.
Last reviewed: 8 June 2026