Percolation Testing in Gloucester

Percolation Tests provides BRE365 soakaway percolation testing and foul infiltration testing across Gloucester and the surrounding Severn Vale.

We are based in Wolverhampton, about 50 miles away, and Gloucester is well inside the area we cover as standard. We have carried out 42 tests within fifteen miles of Gloucester and 118 within twenty-five, so the ground around the town is familiar to us.

Ground conditions in Gloucester

Gloucester sits low in the Severn Vale on heavy alluvial clay, with a high water table in many areas close to the river and the Gloucester and Sharpness Canal. This combination often limits standard soakaway feasibility in parts of the city, making an accurate site-specific percolation test an essential first step rather than a formality.

Ground around Gloucester 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 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 Gloucester

Applications in the Gloucester area are dealt with by Gloucester City 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 Gloucester 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 Gloucester city, Quedgeley, Longlevens, 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 Gloucester. Call 01902 475653 or request a quote online.

Also serving Gloucestershire

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

• Cheltenham

Recent work near Gloucester