SiltTraps

A silt trap should always be installed upstream of your soakaway crate or attenuation tank, catching water before it reaches the main storage system. This allows silt, sediment and grit to settle out in the chamber before the filtered water continues on. Typical locations include car parks, driveways, roof drainage runs and yard areas where surface water picks up debris.

Sizing depends on the catchment area draining into the trap and the amount of silt or debris expected — a small domestic driveway needs far less capacity than a commercial car park or yard. As a guide, larger paved areas or sites prone to heavy debris should use a bigger chamber to reduce how often it needs emptying. If you're unsure, get in touch with our team with your site details and we can help you pick an appropriately sized unit.

This varies with usage and the amount of silt entering the system, but most domestic silt traps are checked and emptied every 6 to 12 months. Commercial or high-debris sites, such as car parks or yards with lots of loose material, may need more frequent attention. Regular inspection is the best way to avoid the trap filling up and losing its effectiveness.

Yes, we stock silt traps across a range of sizes to suit everything from a single domestic driveway through to larger commercial car parks and yards. Brands like Klargester and Clearwater offer units designed for different flow rates and catchment sizes. Choosing the right one comes down to the area being drained and how much silt and debris is expected.

Silt traps themselves don't usually require planning permission, but they're often installed as part of a wider drainage or soakaway system that may fall under building regulations, particularly Part H. If your project involves connecting to a new soakaway or altering existing surface water drainage, it's worth checking with your local building control or a drainage professional before work starts.

A standard silt trap is designed primarily to capture silt, sediment and solid debris by allowing it to settle out of the water flow, and many units also provide a degree of oil separation as a secondary function. However, if your site regularly discharges significant oil or fuel contamination, such as a workshop or fuel storage area, you should look at a dedicated oil separator or interceptor to meet environmental requirements. Get in touch if you're not sure which is right for your site.