BRE 365 Soakage Testing

Book professional soakage testing to determine the permeability of soils for the detailed design of conventional soakaways.

Hassle-free on-site BRE 365 soakage testing from IBEX CE

It is the requirement of the majority of local planning authorities and water authorities that BRE 365 soakage testing is completed prior to the commencement of the detailed design of the conventional soakaways and their installation. IBEX CE is highly experienced in determining soils’ infiltration rates in accordance with BRE Digest 365 ‘Soakaway Design’ BRE, 2016, which is the requirement of most of the local authorities. 

Our on-site soakage tests are completed with the highest precision in alignment with industry-standard procedures for guaranteed accuracy. Upon completion of testing, we provide clients with an easy-to-understand report containing the necessary calculations and a detailed exploratory holes’ log. This report can be submitted in its entirety to local authority planners for the consent of your proposed soakaway design or as part of the drainage strategies.

IBEX Consulting Engineers are industry experts in ground investigation and testing procedures. Contact us today to book your on-site BRE 365 soakage test.

BRE 356 Soakage testing

The BRE Digest 365 soakaway test is the most commonly implemented method for measuring soil permeability for the design of soakaway drainage. 

Guidance published by the Building Research Establishment defines the standardised procedure for effective soakage testing. 

To correctly investigate the porosity of subgrade soils and determine the design of your soakaway, there is a defined procedure for calculating rainfall design values and soils’ infiltration rates. 

This test determines whether the development of a stable, sustainable urban drainage system like the conventional soakaway can be considered within your site boundaries. Alternatively, borehole soakaways might be considered.

soakage testing



BRE 365 soakage testing is frequently completed per the recommendations of a Phase I desk study or by request of local planning authorities. BRE 365 standardised testing is the most precise examination of water absorption rate into the underlying natural subgrade soils. The results of this test dictate the suitability of soil for the construction of soakaways.

Under industry guidance, professional ground investigation consultants from IBEX CE will excavate a trial pit to the target depth. This excavation may be completed using plant machinery or hand-held tools depending on the site conditions and access constraints of the site.  

After the pit is excavated, gravel may be used to retain the stability of the sidewalls of the pit. The pit is then filled with water using a tanker or a 4X4 towed water bowser. On-site water supplies typically don’t supply a sufficient filling rate to complete the test accurately. 

Once filled, the time it takes for the water to disperse from 75% full to 25% is measured to calculate the soil infiltration rate (m/sec). This process is repeated on three consecutive filling and drainage cycles to calculate more accurate and representative infiltration rates. 

engineers at work

What are Soakaways?

As a sustainable alternative to pipeline sewers, soakaways offer numerous advantages for the dispersion of surface run-off water. They are vital in preventing flooding and provide a cost-effective solution to traditional sewer maintenance and replacement. 

A soakaway is a buried form of drainage used to disperse excess surface water, such as during extreme weather conditions. The water is stored and steadily drained into the surrounding subgrade soils without the need for transportation via sewer pipes.

The design and installation procedure are relatively simple. A pit is excavated before placing perforated chambers, which allow for efficient water drainage into the surrounding soil. This mitigates the risk of flooding and offers additional protection for surrounding structures such as building foundations. 

Whilst soakaways are incredibly effective solutions for the dispersal of surface water, not all subgrade soils are permeable enough for the efficient infiltration of excessive amounts of storm water. As a result, a Phase I desk study may suggest the completion of soakage testing. Additionally, local planning authorities now require that BRE 365 soakage tests are completed to determine the subgrade soils’ permeability properties before installing a soakaway.

Book BRE 365 Soakage Test at IBEX CE

BRE 365 Soakage tests allow the investigation of subgrade soil permeability on the site. Upon completion of testing, you will gain access to a factual or interpretive report immediately. Delivery times of factual reports at IBEX CE is normally one day after the completion of site works. 

If you are interested in completing a Phase I desk study on your site to determine the necessity of soakaways, you can find more information here

IBEX Consulting Engineers are committed to practising standardised procedures and measurements. The testing results recorded by our team of chartered engineers will provide you with the data to design the required parameters of your soakaways. 

Contact us using the details below to book BRE 365 soakage testing today. 

Contact Us

‘Geotechnical and Environmental Specialists’

Abbey House, 25 Clarendon Road, Redhill, Surrey, RH1 1QZ

01737 452622 (ext.2622)