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Surface Water Drainage

we provide comprehensive flood defence and surface water drainage solutions — from initial site strategy and SuDS design through to fully engineered systems for construction and long-term management.

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Flood Defence & Surface Water Drainage Services

Our drainage specialists have decades of experience working across the UK — including in areas where Schedule 3 of the Flood and Water Management Act has been implemented — ensuring every design meets both local planning policy and Environment Agency regulations.

Whether you’re developing new housing, expanding commercial premises, or improving existing infrastructure, we create tailored systems that safely and sustainably manage rainfall runoff, reduce flood risk, and protect the environment.

What Are SuDS?

In natural environments, rainfall soaks gradually into permeable surfaces like grass and soil. In built-up areas, hard surfaces such as roads and roofs prevent this process, causing excess runoff, localised flooding, and pollution.

Sustainable Drainage Systems (SuDS) mimic natural processes — capturing and slowing water near where it falls, filtering it naturally, and releasing it safely into the environment.

Key benefits include:

  • Reduced flood risk — Slows runoff and prevents system overloads.

  • Improved water quality — Natural filtration removes sediment and pollutants.

  • Enhanced biodiversity — Ponds, swales, and wetlands support local ecosystems.

  • Better amenity value — Creates greener, more sustainable places to live and work.

SuDS also offer broader environmental benefits — enhancing biodiversity, supporting greener spaces, and contributing to sustainable place-making.

When to Consider One

You may need a flood defence or surface water drainage strategy if:

  • Your site experiences standing water or frequent surface flooding

  • You are submitting a planning application for new development

  • Local authority requests a SuDS or flood risk assessment

  • Your property lies within a flood risk or low infiltration zone

  • You require long-term resilience and compliance with EA or LLFA standards

Why Choose Us?

  • Over 30 years’ experience in drainage design and flood prevention

  • Fully accredited (NADC, SafeContractor, CHAS, ISO 9001)

  • In-depth knowledge of national and local SuDS regulations

  • Complete design-to-installation service

  • Environmentally responsible and cost-effective solutions

Areas We Cover

We’re proud to serve customers throughout Cumbria and beyond, including:

If you’re unsure whether we cover your location, just give us a call — our friendly team will be happy to help.

SuDS Planning Process

Pre-Application & Outline Planning Drainage Strategy

Unblock Cumbria can prepare a policy-compliant outline drainage strategy to support your planning application.
We assess your site’s conditions, propose sustainable drainage solutions (SuDS), and ensure early compliance with planning policy and environmental standards, helping you secure approval at the first stage of your project.

Full Planning

If your development proposal involves constructing a new building or significant site alteration, Unblock Cumbria provides a comprehensive drainage strategy to accompany your full planning application.
Our team designs efficient, sustainable systems that manage surface water effectively while meeting all statutory and planning authority requirements.

Discharge of Conditions

We offer expert support with the discharge of drainage-related planning conditions, ensuring all necessary documentation, calculations, and evidence are prepared and submitted correctly.
Our team will guide you through the process, helping you satisfy local authority requirements swiftly and efficiently.

Detailed Design

Following condition discharge, Unblock Cumbria can progress your project through detailed drainage design, reserved matters, and construction stages.
We provide fully engineered designs, drawings, and calculations ready for contractor use, ensuring your drainage system is robust, compliant, and built to last.

Frequently asked questions

What is the difference between SuDS and traditional drainage?

Traditional drainage systems move water quickly into pipes and sewers, often causing downstream flooding during heavy rain. SuDS (Sustainable Drainage Systems) slow water down, encourage natural infiltration, and reduce pressure on sewers. They use features like permeable surfaces, soakaways, swales and attenuation tanks to manage surface water sustainably while improving environmental performance.

Do I need SuDS for my planning application?

Many new developments, extensions and commercial projects require SuDS as part of planning approval, particularly if surface water cannot discharge into the public sewer. Local authorities often request SuDS designs and calculations upfront. We work closely with planners, architects and builders to ensure your drainage strategy meets all current regulations and planning conditions.

Can SuDS work on clay soil?

Yes — although clay soil drains slowly, SuDS can still be highly effective. Instead of infiltration-based systems, we design solutions such as swales, attenuation tanks, filter drains and controlled discharge systems. The key is choosing SuDS components that manage water safely without relying on rapid soil infiltration. We assess the ground first to determine the best approach.

Are SuDS expensive to maintain?

Maintenance costs vary depending on the system, but most SuDS require less operational upkeep than traditional drainage. Permeable surfaces may need occasional sweeping, swales require seasonal vegetation checks, and soakaways benefit from periodic inspections. Regular maintenance ensures long-term performance, reduces flooding risk and helps keep systems compliant with planning conditions.

Can you retrofit SuDS to existing properties?

Absolutely. SuDS are not just for new builds — they can be retrofitted into homes, gardens, car parks and commercial sites with drainage problems. Retrofit solutions may include permeable driveways, soakaways, rain gardens or attenuation crates. We assess the available space and ground conditions to design a system that improves drainage without major disruption.

How do I know which SuDS system is right for my site?

Choosing the correct SuDS method depends on soil type, site levels, available space and where the water needs to go. We carry out testing, surveys and calculations to model runoff volumes and design the safest, most efficient solution. Whether it’s infiltration, attenuation or controlled discharge, we tailor the system to your property’s needs.

Can SuDS help reduce flooding around my property?

Yes. SuDS are specifically designed to manage rainfall more effectively by slowing water flow, increasing storage and allowing safe infiltration where possible. They significantly reduce surface water runoff, preventing pooling and overwhelming of drainage systems. A well-designed SuDS installation is one of the most effective long-term strategies for reducing flood risk.