Percolation Tests in England: Compare the Test Purpose, Site Work and Report

Compare PercolationTests.co.uk and Soakaway Drainage by test purpose first: both advertise BRE 365 surface-water testing and BS 6297 foul-drainage testing, but their coverage and pricing information differ.[1][2] Confirm the required test with your drainage designer before comparing itemised quotations.

Compare purpose, coverage and published pricing

PercolationTests.co.uk

• Test purpose: Offers BRE Digest 365 surface-water soakaway testing and separate BS 6297/Part H foul-drainage testing.[1]
• Confirmed service area: Percolation Tests is based in Wolverhampton and covers the Midlands, Welsh borders and Cheshire as standard, travelling well beyond those areas when the job calls for it.[1]
• Published pricing: The cited service page gives no fixed price. Quotations depend on trial-pit numbers, access and whether surface-water testing, foul testing or both are needed.[1]

Soakaway Drainage

• Test purpose: Advertises BRE365 soakaway tests and BS6297 foul-water drainage tests.[2]
• Confirmed service area: The company identifies a Gloucester, UK address and advertises nationwide service; confirm attendance at your England postcode.[2]
• Published pricing: BRE365 tests are £249–£799 per test; BS6297 foul-water tests are £199–£699 per test; drainage reports start at £99.[2]

PercolationTests.co.uk says it owns its machinery and does not subcontract digging; ask for excavation to be itemised rather than assuming it is included.[1] Soakaway Drainage advertises a “whole package”, but its package inclusions are not itemised on the cited page.[2] Ask whether the separately advertised report and site works are included in its test price.

Choose surface-water testing, foul testing or both

BRE 365 testing supplies infiltration evidence for rainwater soakaway or infiltration-system design. BS 6297 foul testing concerns drainage fields serving septic tanks or package treatment plants.[1][6]

PercolationTests.co.uk and Tankology describe separate tests.[1][6] JDP’s foul-water guide, last reviewed in June 2020, says the test procedure may be similar but suitability calculations may differ.[5] The practical distinction is the design purpose: do not substitute a surface-water result for foul-drainage-field evidence.[1][6]

If both rainwater infiltration and private foul drainage are proposed, specify both purposes separately. PercolationTests.co.uk says it can carry out both test types during one visit.[1] Ask your drainage designer or report recipient to confirm what the project needs before booking.

Agree locations, depths and acceptance requirements

Send the tester a marked site plan showing the proposed drainage layout and depth, the postcode, relevant planning-condition wording, and the report recipient’s expectations.[1][3][6] Testing should relate to the intended infiltration location and design depth, rather than an unspecified spot elsewhere on the plot.[3][4]

Ask your drainage designer and relevant approving body to confirm the evidence and acceptance requirements. Agree who will specify the locations, depths and number of pits before instructing the tester.

For foul drainage, JDP’s guide advises an England groundwater-source-protection search and a trial site assessment hole before percolation testing to identify protected supplies and the local groundwater table. It also states minimum drainage-field distances of 10 metres from any watercourse, 15 metres from any building and 50 metres from any water supply.[5] Use that older guidance to prompt project-specific checks, not as a complete current legal checklist; ask who will undertake and report the assessment.

Compare excavation, water and reinstatement

Send both providers the same quotation checklist. Tankology gives a typical professional wastewater percolation-test cost of around £300–£600 including VAT, depending on the site, excavation and reporting scope. It warns buyers not to assume digging, machinery, water, a groundwater trial hole or reinstatement is included.[6] Request written confirmation of:

• Test scope: purpose; number, locations, depths and dimensions of pits or holes; repeated fills; groundwater assessment; and charges for additional locations or return visits. GeoSmart describes BRE Digest 365 soakage trial pits as 1 m to 3 m long and 0.3 m to 1 m wide, at the anticipated SuDS feature’s depth.[4][6]
• Site works: who excavates; machinery and transport; access requirements; water supply or delivery; safety arrangements; backfilling and reinstatement.[4][6]
• Deliverables and price: calculations, photographs, report format, design sizing, travel, VAT treatment and itemised optional work.[6]

GeoSmart advises that nobody should enter a trial pit and notes that a water bowser may be needed.[4] Leave excavation and testing arrangements to the appointed contractor.

PercolationTests.co.uk describes three timed fills per pit, with full drainage between fills.[1] Ask Soakaway Drainage to specify its repeat-testing scope rather than assuming the advertised price covers equivalent work.

Specify the report your designer needs

Agree report contents before appointment so the results support design calculations, rather than merely record attendance.[3][6] Use the following as commissioning specifications for your designer to confirm.

Surface-water report

Request identified test locations and depths, ground and groundwater observations, recorded water levels and timings, calculated infiltration rates with units, the test method and commentary on infiltration suitability.[3][4]

Ask which measurement records accompany the report. Clear Environmental describes reporting rates and suitability; GeoSmart describes recording the water-level/time evidence used to calculate rates.[3][4]

Clear Environmental describes handing results to a drainage engineer to finalise the design.[3] Confirm whether storage calculations, soakaway sizing, drawings and any wider drainage strategy are included or separately commissioned; testing and completed design are different deliverables.[3][4][6]

Foul-drainage report

Request property details and test date, hole locations and dimensions, ground and weather conditions, timed water-level readings, Vp values, photographs, and comments on consistency and limitations.[6] Include groundwater-assessment findings where commissioned.[6]

Confirm sizing separately. Tankology describes indicative drainage-field sizing as an optional inclusion, not an automatic deliverable.[6] Ask each provider to price the agreed report specification and identify any sizing work separately.

Tankology describes a test report as evidence for assessment and design, not an approval certificate.[6] Soakaway Drainage’s claim that its reports satisfy planning and Building Control requirements, and Clear Environmental’s compliance statements, should not be treated as guarantees of project-specific acceptance.[2][3][6]

Agree what happens if infiltration is unsuitable

PercolationTests.co.uk says it supplies failed-test evidence to support an alternative drainage approach and can assist with a drainage strategy.[1] Ask whether that advice is separately charged.

Have the quotation identify charges for another test location, further investigation and return visits—potential extras highlighted by Tankology.[6] Ask the designer how suitability will be assessed rather than relying on a single surface-water rate as a universal pass/fail threshold.

What to confirm with each provider

• Schedule: obtain a test date and report-delivery deadline. PercolationTests.co.uk allows up to 48 hours for a fee proposal; that is not the testing or reporting timescale.[1]
• Written terms: the cited PercolationTests.co.uk and Soakaway Drainage pages do not state refund terms, fixed test durations or report-delivery deadlines.[1][2] Check cancellation terms and charges for an unsuitable result before appointment.
• Final scope: confirm the test purpose, postcode coverage, itemised site work, total price and designer-agreed report, with design work identified separately.

PercolationTests.co.uk offers site-specific quotations and named standard coverage; Soakaway Drainage publishes price ranges and advertises nationwide coverage, but package inclusions still need confirmation.[1][2] Compare the total cost of the same agreed work, not the headline test prices alone.

References

1. Percolation Testing Services | BRE365 and BS 6297 Tests (percolationtests.co.uk)
2. Building Regulations Percolation Test Company (soakawaydrainage.com)
3. Infiltration Testing For Soakaway Design in the UK – Clear Environmental (clearenviro.co.uk)
4. What is Infiltration Testing? | Blog (geosmartinfo.co.uk)
5. How to perform a percolation test | JDP (jdpipes.co.uk)
6. Percolation Test Cost in England and Wales: 2026 Guide | Tankology (tankology.co.uk)