Percolation Tests provides BRE365 soakaway percolation testing and foul infiltration testing across Rugby and the surrounding rural district.
We are based in Wolverhampton, about 39 miles away, and Rugby is well inside the area we cover as standard. We have carried out 21 tests within fifteen miles of Rugby and 50 within twenty-five, so the ground around the town is familiar to us.
Ground conditions in Rugby
Rugby sits near the source of the River Avon on Mercia Mudstone clay with pockets of glacial till, both of which tend to drain slowly. The town has also seen significant new-build development in recent years, meaning made ground and engineered fill are an increasingly common factor to account for alongside the natural clay geology.
Mudstone and clay drain slowly, so sites around Rugby more often return marginal or failing rates than free-draining ones. That is not automatically bad news — a measured rate, even a poor one, is what the drainage engineer needs to size the system or to justify a different approach. What causes problems is assuming a rate. River terrace gravels along the valleys can drain far better than the surrounding ground, and the only way to know which you have is to dig and time it.
What we test for
- BRE365 percolation testing for surface water soakaway design
- Foul effluent infiltration testing (Part H) for septic tanks and treatment plants
- Drainage strategy support for planning submissions
How the test is carried out
BRE Digest 365 sets out the procedure, and it is more demanding than it sounds. A single filling of a single hole proves very little.
- Trial pits are excavated at the proposed soakaway position, taken down below the level the soakaway will sit at. The number depends on the site and the design.
- Each pit is filled to at least 75% of its effective storage depth, which is where the timed measurement starts from.
- Each pit is then filled and timed three times over, measuring the fall from 75% to 25% of the effective depth.
- The slowest of those runs is carried into the calculation, which keeps the resulting design conservative.
The three fills and the draining time between them are why this cannot be rushed. A number produced quickly is a number that tends to get challenged.
Planning conditions in Rugby
Applications in the Rugby area are dealt with by Rugby Borough Council, and drainage conditions are attached routinely — particularly on rural plots, barn conversions and self-builds with no mains surface water connection. The condition normally asks for infiltration testing to BRE365 and a soakaway design based on the result, approved before work starts.
Testing early is worth the trouble. If infiltration turns out not to be viable the drainage strategy has to change, and discovering that after the groundworks are priced is an expensive surprise.
Septic tanks and foul drainage
Surface water and foul drainage are tested differently, and the results are not interchangeable. A drainage field for a septic tank or treatment plant is sized using BS 6297, which Part H of the Building Regulations refers to. If your site near Rugby needs both a soakaway and a drainage field, we can carry out both tests in one visit rather than two.
What you receive
- A full report with the recorded times for every pit and every fill
- The calculated infiltration rate, ready to hand to your engineer or planner
- Trial pit locations and depths
- Photographs of the testing on site
- A clear statement of whether a soakaway is viable, and if not, why not
Coverage
We test across Rugby, Dunchurch, Long Lawford, and the surrounding villages. Available Monday to Friday.
Get a quote
Contact us for a free, no-obligation quote for percolation or infiltration testing anywhere in Rugby. Call 01902 475653 or request a quote online.
Percolation testing around Rugby
Each dot is a site we have tested. 3 within ten miles of Rugby, 43 within twenty-five.
Also serving Warwickshire
This page is part of our coverage across Warwickshire, which also includes:
Recent work near Rugby
