Surface Water Drainage & SuDS
We design sustainable drainage systems that satisfy planners, LLFAs, and water companies. Our engineers support projects from pre-application concepts to discharge of conditions.
Drainage strategies that secure approval.
We design SuDS management trains, coordinate with utilities, and deliver clear design documentation. Our team integrates drainage with flood risk mitigation and highways layouts so schemes work as a whole.
We advise on Schedule 3 compliance in Wales and local authority requirements across the UK.
Delivering SuDS from concept to build-out.
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Early feasibility
We assess site constraints, infiltration potential, and discharge routes.
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Concept strategy
We design management trains and draft drainage layouts.
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Detailed design
We size storage, model flows, and coordinate with highways geometry.
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Planning support
We answer technical queries and support condition discharge.
We align drainage with planning outcomes.
- We design SuDS that satisfy LLFAs and water companies.
- We integrate flood risk, highways, and civils in one team.
- We deliver clear drawings and maintainability plans.
Tools we use
MicroDrainage, AutoCAD Civil 3D, GIS, and bespoke spreadsheets.
Map your site in minutes.
Draw your site boundary and get an instant flood risk and constraints overview tailored to your parcel. Use it to brief your team, test planning viability, and move forward with clarity before commissioning detailed studies.
Map Your Site NowWhy map my site?
- Get an instant preliminary assessment of your site's constraints.
- Understand flood risk zones before investing in detailed studies.
- Identify potential planning issues early in your project.
- Receive a tailored quote based on your actual site boundaries.
- No obligation, completely free to use.
Frequently asked questions
- What is a SuDS management train?
- A SuDS management train is a sequence of drainage features that treat and attenuate surface water runoff in stages before it leaves the site. It typically moves water from source controls like permeable paving through conveyance features such as swales to storage elements like attenuation basins, improving water quality at each stage.
- Do I need a drainage strategy for planning?
- Most planning applications for new development require a surface water drainage strategy. The strategy must demonstrate how runoff will be managed to prevent increased flood risk, typically limiting discharge to greenfield runoff rates. Your local planning authority and Lead Local Flood Authority will confirm the specific requirements.
- What is the difference between foul and surface water drainage?
- Foul drainage carries wastewater from toilets, sinks, and appliances to a treatment works, while surface water drainage handles rainwater runoff from roofs, roads, and paved areas. Planning authorities require separate systems and expect surface water to be managed through SuDS rather than connected to the foul sewer.
- Who approves SuDS designs?
- In England, the Lead Local Flood Authority (LLFA) is a statutory consultee on major applications and reviews the drainage strategy. In Wales, the SuDS Approving Body (SAB) must approve all drainage designs before construction. Water companies also review designs where adoption is proposed.
- How much does a drainage strategy cost?
- Costs depend on the size and complexity of the development, the site's ground conditions, and whether infiltration testing or hydraulic modelling is needed. A strategy for a small residential scheme will be significantly less than a multi-phase masterplan. We provide fixed-fee proposals after scoping the site.