Percolation Tests provides BRE365 soakaway percolation testing and foul infiltration testing across Crewe and the surrounding Cheshire East area.
We are based in Wolverhampton, about 38 miles away, and Crewe is well inside the area we cover as standard. We have carried out 14 tests within fifteen miles of Crewe and 47 within twenty-five, so the ground around the town is familiar to us.
Ground conditions in Crewe
Crewe sits on the Cheshire Plain, an area of glacial boulder clay and sand deposits left behind by past ice sheets. Drainage performance can vary considerably across short distances depending on which glacial deposit dominates a given site, and Crewe’s railway and industrial heritage also means made ground is a relevant factor in parts of the town.
The Cheshire Plain carries some of the thickest glacial till in the country, and around Crewe that boulder clay is often the deciding factor rather than the rock beneath it. Till drains poorly and can be many metres deep, so a good result usually depends on finding a sand or gravel lens within it. Those lenses are unpredictable across a single field, which is exactly why a site-specific test is required rather than an assumed rate for the area.
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 a BRE365 test involves
The method comes from BRE Digest 365, and it takes longer than most people expect. It is not one hole and a stopwatch.
- Trial pits are dug where the soakaway is proposed and taken below its intended base. How many depends on the size of the site and what the drainage design needs.
- Each pit is filled to at least 75% of its effective storage depth before timing begins.
- Each pit is then filled and timed three separate times, recording how long the water takes to fall from 75% to 25% of the effective storage depth.
- The slowest result is the one used, so the design is based on the worst case rather than a flattering one.
Because every pit is tested three times and has to drain fully in between, a proper test is not an hour’s work. We would rather tell you a site is unsuitable than hand over a figure that will not stand up at planning.
Planning conditions in Crewe
Applications in the Crewe area are dealt with by Cheshire East 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 Crewe 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 Crewe, Sandbach, Alsager, 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 Crewe. Call 01902 475653 or request a quote online.
Nearby areas we cover
Recent work near Crewe
Percolation testing around Crewe
Each dot is a site we have tested. 6 within ten miles of Crewe, 41 within twenty-five.