Percolation Tests carries out BRE365 percolation and foul infiltration testing across Shrewsbury and the surrounding Shropshire countryside, supporting planning applications for both town and rural sites.
We are based in Wolverhampton, about 27 miles away, and Shrewsbury is well inside the area we cover as standard. We have carried out 80 tests within fifteen miles of Shrewsbury and 134 within twenty-five, so the ground around the town is familiar to us.
Ground conditions in Shrewsbury
Shrewsbury sits within a loop of the River Severn on predominantly sandstone geology, which generally percolates reasonably well, though river terrace deposits near the water and glacial till in surrounding rural areas can behave very differently. Rural plots just outside the town, common for self-build projects in this area, often show more variable results than the town centre itself.
The older mudstones and sandstones around Shrewsbury weather to variable depths, and the amount of superficial cover changes quickly across a plot. Valley floors often carry alluvium and river gravels that behave completely differently from the slopes above them. Sloping sites bring a second consideration: a soakaway has to be positioned so that what it discharges does not resurface further down or affect a neighbouring property, which sometimes matters more than the raw infiltration figure.
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 Shrewsbury
Applications in the Shrewsbury area are dealt with by Shropshire 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 Shrewsbury 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 Shrewsbury town and the surrounding villages, including Bayston Hill, Shawbury, Bicton, and Meole Brace. Available Monday to Friday.
Get a quote
Contact us for a free, no-obligation quote for percolation or infiltration testing anywhere in Shrewsbury. Call 01902 475653 or request a quote online.
Percolation testing around Shrewsbury
Each dot is a site we have tested. 34 within ten miles of Shrewsbury, 111 within twenty-five.
Also serving Shropshire
This page is part of our coverage across Shropshire, which also includes:
Recent work near Shrewsbury
Percolation Testing in Shrewsbury
