Common questions.

Either way works. We're happy to take instructions directly from a developer or self-builder, or to work alongside your planning consultant or drainage/civil engineer if they're coordinating it on your behalf.

Infiltration testing (to BRE 365) is generally used to inform surface water drainage design, such as soakaways or permeable paving. Percolation testing follows current building regulations guidance and is generally used for foul drainage fields.

Many local sewer networks were built decades ago for a much smaller population, and drainage policy used to be looser about routing surface water into foul sewers. With sewers now regularly surcharging, councils are tightening requirements at planning stage to manage flood risk and reduce pressure on the network.

Normally across the winter months, roughly September/October through to April/May, when groundwater levels are at their highest. We take bookings for the coming season in advance, so it's worth getting in touch early.

Ideally your proposed drainage plans. If those aren't ready yet, architectural layouts (existing and proposed) are enough for us to identify approximate test locations and depths, alongside BGS and local borehole records.

It happens, and it isn't a dead end — a failed test is valid evidence that can justify an alternative drainage solution, such as a connection to the public sewer, as part of your application.

We offer a rapid-response booking service, though exact timing for the visit itself depends on current bookings — particularly for groundwater monitoring during the winter season. Once testing is complete, though, you're not waiting long: results and a full report are turned around the next day (subject to terms and conditions).