Percolation Tests carries out BRE365 soakaway percolation testing and foul infiltration testing across Macclesfield and the surrounding Cheshire East foothills.
We are based in Wolverhampton, about 46 miles away, and Macclesfield is well inside the area we cover as standard. We have carried out 16 tests within twenty-five miles of Macclesfield.
Ground conditions in Macclesfield
Macclesfield sits at the edge of the Cheshire Plain where it meets the Pennine foothills, giving the area a mix of glacial clay in the lower ground and gritstone-influenced, generally better-draining soils higher up towards the Peak District boundary. This transition means percolation rates can change quickly depending on elevation and exact site location.
The Cheshire Plain carries some of the thickest glacial till in the country, and around Macclesfield 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
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 Macclesfield
Applications in the Macclesfield 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.
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 Macclesfield 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 Macclesfield, Bollington, Prestbury, 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 Macclesfield. Call 01902 475653 or request a quote online.
Nearby areas we cover
Recent work near Macclesfield
Percolation testing around Macclesfield
Each dot is a site we have tested. 3 within ten miles of Macclesfield, 15 within twenty-five.