Percolation Testing in Sutton Coldfield

Sutton Coldfield and the Royal Town’s surrounding villages are well within our regular working area. We carry out BRE365 soakaway percolation testing and BS 6297 foul infiltration testing across Sutton Coldfield and the surrounding area.

We have tested 9 sites within five miles of Sutton Coldfield, 40 within ten and 143 within twenty-five, so the ground here is familiar to us. Of the 40 tests within ten miles, 36 gave a usable result and 4 showed infiltration too poor for a soakaway, which is exactly why a test is needed before the design is fixed.

Ground conditions in Sutton Coldfield

Much of Sutton Coldfield sits on the Triassic Sherwood Sandstone, including pebbly beds, with glacial sands and gravels over it. The open heathland of Sutton Park reflects those free-draining soils. Further east, towards Walmley and Minworth, the ground changes to Mercia Mudstone and clay.

That makes Sutton one of the better areas for soakaways, but not everywhere. A plot on sand and gravel near the Park may drain well, while one on clay a mile or two east may not. Where the ground is very permeable, the Council will also want to see that groundwater is not close to the base of the soakaway, which we note in the report.

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 (SuDS) support for planning applications

How the test is carried out

BRE Digest 365 sets out the procedure. A single filling of a single hole proves very little.

• Trial pits are dug at the proposed soakaway position, taken below the level the soakaway will sit at.
• Each pit is filled to at least 75% of its effective depth, where the timed measurement starts.
• Each pit is filled and timed three times, measuring the fall from 75% to 25% of the effective depth.
• The slowest run is used in the calculation, which keeps the design conservative.

Planning conditions in Sutton Coldfield

Sutton Coldfield is part of Birmingham, so planning and drainage conditions are dealt with by Birmingham City Council as both planning authority and Lead Local Flood Authority. Soakaway designs are expected to be backed by BRE365 results.

Testing early is worth it. If infiltration is not viable the drainage strategy has to change, and finding that out 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. We can carry out both 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 for 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 cover the whole of Sutton Coldfield, including Four Oaks, Mere Green, Little Aston, Walmley, Wylde Green, Boldmere and Minworth. Available Monday to Friday.

Get a quote

For a free, no-obligation quote, call 01902 475653, send an enquiry, or if you know where the pits need to go, use our detailed quote request.

Also serving the West Midlands

This page is part of our coverage across the West Midlands, which also includes:

• Birmingham
• Tamworth
• Lichfield
• Walsall