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The Cost of Unforeseen Infiltration Problems

There is a lot at stake if you don’t have reliable infiltration information before you design your soakaway and drainage scheme…
Our Soakage Testing will help you understand the permeability of your site, so you can make even better design decisions.

Environmental Consultants Committed to Getting Your Site Approved and Built

Your specialist Environmental Consultant is part of a dedicated team of Chartered professionals who have been successfully gaining regulatory approval for clients all over the UK, ensuring that their sites are safe and compliant places to live and work.

Our BRE 365 infiltration tests are expertly prepared by experienced consultants who are committed to providing you with a technically robust assessment that is tailored to meet your plans for the site.

  • Tick Icon BRE 365 compliant, ensuring British Standards are followed
  • Tick Icon Technically robust, written with an engineer in mind
  • Tick Icon Turnkey solution, undertaken by in-house experts

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Answer a few questions, so together we can come up with a plan that fits your timescales and budget.


Soakage Testing

We work through the complex process of organising the site works and carrying out the Soakage Testing at the site.


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Written with the local authority in mind to gain approval, tailored for you so you know what action to take for design purposes.

Could You Require A Soakage Test?

Soakage tests, also known as percolation or infiltration tests, are used to calculate the rate at which water infiltrates the soil at a specific location.

These infiltration rates are often used to support the design of surface water drainage schemes and SuDS.

We have experienced consultants who can undertake soakage tests to the Building Research Establishment Digest 365 (BRE 365) guidance.

Soakage Testing

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.

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