Percolation Tests provides BRE365 soakaway percolation testing and foul infiltration testing across Royal Leamington Spa and the surrounding area.
We are based in Wolverhampton, about 33 miles away, and Leamington Spa is well inside the area we cover as standard. We have carried out 31 tests within fifteen miles of Leamington Spa and 83 within twenty-five, so the ground around the town is familiar to us.
Ground conditions in Leamington Spa
Leamington Spa sits on Mercia Mudstone clay along the River Leam, with the town’s historic spa wells a reminder of the area’s particular hydrogeology. Clay-dominant ground here typically percolates slowly, and combined with a relatively high water table in places near the river, soakaway feasibility should always be confirmed with a site-specific test rather than assumed.
Mudstone and clay drain slowly, so sites around Leamington Spa 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
What the testing actually involves
The procedure is defined by BRE Digest 365. It is worth knowing what it requires, because a test that cuts corners is easy to spot at planning.
- Trial pits go in where the soakaway is proposed, dug below the depth it will eventually sit at. How many is a matter of site size and design.
- Each pit is filled to at least 75% of its effective storage depth, the point the timed measurement runs from.
- Each pit is then filled and timed on three separate occasions, recording the fall from 75% to 25% of the effective storage depth.
- The slowest run governs the calculation, so the figure errs towards caution rather than optimism.
All of that takes time, and we plan the visit around it. If the ground will not support a soakaway we will say so plainly rather than produce a figure that fails later.
Planning conditions in Leamington Spa
Applications in the Leamington Spa area are dealt with by Warwick District 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 Leamington Spa 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 Leamington Spa, Whitnash, Cubbington, 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 Leamington Spa. Call 01902 475653 or request a quote online.
Percolation testing around Leamington Spa
Each dot is a site we have tested. 16 within ten miles of Leamington Spa, 70 within twenty-five.
Also serving Warwickshire
This page is part of our coverage across Warwickshire, which also includes:
Recent work near Leamington Spa
