What a drainage field is
A drainage field is a network of perforated pipes laid in gravel-filled trenches. It spreads the liquid from a septic tank or treatment plant over a large area of soil, so the soil can treat it. New drainage fields should meet BS 6297:2007.
What a soakaway is
A soakaway is usually a single pit or crate that lets clean rainwater from roofs and paths drain into the ground. It isn't designed to treat sewage.
Why it matters under the rules
Under the general binding rules, a septic tank must discharge to a drainage field. Soakaways installed after December 2007 can't meet the rules for sewage, so an older system that drains to a pit or a soakaway may need upgrading to a proper drainage field.
Keep rainwater out of the septic system
Rainwater going into the septic tank or drainage field can overload it, especially in wet weather. Roof and surface water should go to its own soakaway.
How to tell which you have
Old paperwork, the layout of the garden, and a survey can tell you. If wet ground, smells or slow drains point to a problem, it's worth finding out before it gets worse.
Want a clear answer for your property?
Tell us what's happening and roughly where you are. No need to know what type of system you have.