Percolation Testing in Cheltenham

Percolation Tests carries out BRE365 soakaway percolation testing and foul infiltration testing across Cheltenham and the surrounding Cotswold edge.

We are based in Wolverhampton, about 47 miles away, and Cheltenham is well inside the area we cover as standard. We have carried out 34 tests within fifteen miles of Cheltenham and 101 within twenty-five, so the ground around the town is familiar to us.

Ground conditions in Cheltenham

Cheltenham sits at the foot of the Cotswold escarpment, where limestone geology on the higher ground to the east generally percolates well, while the lower town itself sits on Lias clay that drains considerably more slowly. This contrast within a small area makes Cheltenham a good example of why percolation results can’t be assumed from one part of town to another.

Ground around Cheltenham changes character sharply between the vale and the scarp. The limestone of the Cotswold edge can be fissured and drain very quickly, while the clays of the Severn Vale below hold water. Low ground near the river also sits close to the water table, and BRE365 requires the base of a soakaway to stay clear of it — a site can fail on groundwater alone regardless of how the soil performs.

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 Cheltenham

Applications in the Cheltenham area are dealt with by Cheltenham Borough 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 Cheltenham 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 Cheltenham, Bishop’s Cleeve, 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 Cheltenham. Call 01902 475653 or request a quote online.

Also serving Gloucestershire

This page is part of our coverage across Gloucestershire, which also includes:

• Gloucester

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