Percolation Tests carries out BRE365 soakaway percolation testing and foul infiltration testing across Warwick and the surrounding area.
We are based in Wolverhampton, about 31 miles away, and Warwick is well inside the area we cover as standard. We have carried out 35 tests within fifteen miles of Warwick and 94 within twenty-five, so the ground around the town is familiar to us.
Ground conditions in Warwick
Warwick sits predominantly on Mercia Mudstone clay, the same slow-draining deposit found across much of Warwickshire, though river terrace sands and gravels near the Avon can percolate noticeably better. Given how much this can vary within the town itself, a site-specific test is the only reliable way to know whether a standard soakaway will work or whether an alternative drainage strategy is needed.
Mudstone and clay drain slowly, so sites around Warwick 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 Warwick
Applications in the Warwick 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.
Foul drainage and septic tanks
If the site is not on mains foul drainage that is a separate test. Drainage fields for septic tanks and package treatment plants are sized by the method in BS 6297, referenced by Part H of the Building Regulations, and that figure is not interchangeable with a BRE365 result. Plenty of rural sites around Warwick need both, and we can do them on the same visit.
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 Warwick, Whitnash, Bishops Tachbrook, 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 Warwick. Call 01902 475653 or request a quote online.
Percolation testing around Warwick
Each dot is a site we have tested. 16 within ten miles of Warwick, 76 within twenty-five.
Also serving Warwickshire
This page is part of our coverage across Warwickshire, which also includes:
Recent work near Warwick
