This is a question we’re frequently asked by developers — so rather than explain it again and again, we’ve created this article to help clarify the importance of BRE365 percolation testing and how it relates to your SuDS (Sustainable Drainage Systems) report.
Why Are SuDS Reports Required?
A SuDS report or SuDS assessment is typically required to support a planning application or to discharge planning conditions relating to surface water runoff. The purpose of the report is to demonstrate that your proposed development will not increase flood risk — either on your site or elsewhere.
Local authorities need to know how you intend to manage surface water runoff at the planning stage. Without this, you risk receiving planning permission without a drainage solution, leaving you with a development site and no approved means of dealing with surface water.
Why Is This Important?
Urbanisation and increasingly severe storm events have overwhelmed traditional drainage systems. Many existing networks simply cannot cope with the peak flow of water during rainfall, leading to flooding of pipe systems, watercourses, and even coastal areas.
The Role of SuDS
The only way to alleviate this growing risk is to ensure all new developments incorporate Sustainable Urban Drainage Systems. SuDS reduce flood risk by slowing down the flow of water and encouraging infiltration where possible — keeping runoff as close to its source as possible.
We understand that development already comes with high costs, and that the number of required planning reports continues to increase. Materials, labour, and time are all under pressure. That’s why at Nimbus Engineering, our approach is always client-focused.
We work with you to ensure we meet the mandatory SuDS requirements set out by local and national policy — helping your application succeed, your planning conditions get discharged, and your development move forward without delays.
Why BRE365 Infiltration Tests Matter
In many cases, your site’s ability to drain water naturally (via the ground) can only be confirmed by a BRE365 Infiltration Test (also known as a percolation test). This test is used to assess whether infiltration SuDS features (such as soakaways or permeable paving) are suitable for your site.
This information is essential for:
- Designing effective drainage strategies
- Satisfying the requirements of your Lead Local Flood Authority (LLFA) or SuDS Approval Body (SAB)
- Ensuring your connection to a public sewer is only pursued if infiltration isn’t viable
With over 15 years of UK-wide experience, our team understands the varying requirements of LLFAs across England and Wales — allowing us to provide solutions that are compliant, practical, and tailored to your development.
What If I Don’t Provide a SuDS Report?
In rare cases where SuDS reports weren’t requested at the planning stage, water authorities may still demand them before approving any discharge connection into their combined or surface water sewer network. This is because many of these systems are already at capacity and cannot handle additional load.
Our Advice
At Nimbus Engineering, we’re not here to sell you reports you don’t need — we’re here to help you navigate planning, avoid delays, and get your development connected efficiently and compliantly. From initial application to final connection, we provide up-to-date drainage advice and expert support.
Still unsure? Contact our team at 📧 info@nimbusengineering.co.uk – we’re here to help with SuDS reports, BRE365 testing, and drainage design across the UK.
