Soakage Testing to Check Your Ground Drains

Our experienced consultants can undertake soakage tests on your site to the BRE 365 guidance. BRE 365 testing requires access to the excavate trial pits and carry out testing. Soakaways must be able to show that water within the pits drains so that it can still provide the run-off support for torrential rainfall.

You can reduce delays by undertaking soakage testing at an early stage in the project. This will highlight any potential drainage issues and provide you with the knowledge you need to submit your planning application with a robust drainage scheme.

We take pride in our environmental multi-disciplinary team, which provides added value to our clients. Our Soakage Testing services can be complemented with our in-house ability to undertake ground water monitoring, geotechnical investigations and Contaminated Land Assessment. This allows us to provide the very best advice, design and deliver schemes in accordance with local and national policy requirements.

Where space constraints or ground conditions require different testing, a Falling Head Test may be more appropriate. This is a test where infiltration rates are estimated from tests in boreholes rather than a trial pit.

Percolation tests, as set out in the Building Regulations – Part H may also be needed to determine the suitability of drainage fields for foul water treatment. The NHBC also provides detailed guidance on soakaways should be designed.

Where a Phase 2 Site Investigation is required at pre-planning stage, it is often most cost effective and less disruptive to undertake infiltration testing at the same time. Groundwater monitoring may also be required to ensure that any drainage strategy is designed with consideration to groundwater fluctuations. This may also form an important part of a Basement Impact Assessment in a number of London boroughs.

Our in-house drainage and flood risk consultant can use this information within the design of your drainage strategy. LLFAs will require evidence of infiltration rates where full planning applications are submitted.

These are some frequently asked questions about soakage testing:

What is BRE 365 Testing?
These are written Building Research Establishment Digest 365 (BRE 365) guidance on how a soakage test should be calculated. Information from this test can inform your surface water soakaway design to ensure you are compliant with regulations including the NHBC.

What does soakage testing involve?
First a trial pit is excavated, usually by a mini digger. This pit acts as a sort of model of the intended soakaway. The pit is then filled with water repeatedly, and in a short space of time while the rate of water draining away is being measured.

These calculations can then be used to help determine the size of the soakaway required.

What if you can’t dig a trail pit on my site?
Where space constraints require different testing, a Falling Head Test may be more appropriate. This is a test where infiltration rates are estimated from tests in small but deeper boreholes rather than a trail pit.

How long does soakage testing take?
Our consultant and necessary equipment will need to be booked to visit your site to undertake the testing, which is usually within one to two weeks. Once the testing has taken place initial results can be available within 24 hours but full a detailed report of the results can be provided within one week.

How can I book soakage testing?
If you are unsure as to whether you require a soakage testing, please give us a call. Alternatively, please send an email to info@lustreconsulting.com and provide us with the site location and description of the proposed development.