The disturbing revelation that almost 30,000 home builds across the UK are being stalled due to sewerage capacity constraints is a wake-up call.
Martin Lambley is senior product manager – climate resilience at Wavin
Despite more than £2.3bn spent since 2020 on network enhancements, planning permissions remain blocked, even where water companies haven’t objected to schemes, highlighting a systemic disconnect between infrastructure readiness and housing delivery. This conundrum demands a new perspective: one where grey infrastructure such as engineered attenutation systems work hand in glove with green SuDS principles under Defra’s new National Standards for Sustainable Drainage Systems
The Defra Standard: Harmonising SuDS with housing delivery
The Department for Environment, Food & Rural Affairs (Defra)’s updated National SuDS Standards, released in mid-2025, set a deliberate hierarchy for managing surface water from collection for reuse to infiltration and controlled discharge only resorting to sewers as a last option.
These standards focus on four key pillars: quantity control, water quality, amenity, and biodiversity. By elevating functional, multi-benefit SuDS, the standards encourage engineering solutions that deliver more than drainage. They deliver resilience, ecological value, and community amenity.
Engineers at the helm: Aligning delivery with vision
Here’s how engineering and infrastructure professionals can deliver homes without building delays:
1. Champion early – integrated design
Collaborate early with SuDS Approving Bodies, local flood authorities, water companies, planners and drainage manufacturers like Wavin. This builds alignment between drainage solutions and sewer capacity—keeping housing schemes on track.
2. Deploy multi-purpose SuDS features
From rain gardens and blue-green roofs to infiltration strips and attenuation systems, SuDS need not be an afterthought. Designed well, they fulfill function while enhancing biodiversity, aesthetic value, and community space.
3. Reduce reliance on combined sewers
By following Defra’s discharge hierarchy and using evidence-based designs, we reduce pressure on overtaxed sewer systems and avoid planning bottlenecks.
4. Design for climate resilience and longevity
Incorporate climate allowances, robust maintenance regimes, and future-proofed systems. Resilience, not just compliance, must define our approach.
Case study: Worksop – How AquaCell NG accelerated delivery
- Project: 110-unit Bellway Homes development, Worksop (pictured)
- Contractor: M & J Evans
- Product: Wavin’s AquaCell NG geocellular attenuation system
Facing tight site access, limited storage, and frost-bound December conditions down to –7 °C, the project required an agile, high-performance drainage solution. AquaCell NG delivered:
- Rapid installation: Push-fit connectors, hand-grips, and intuitive design enabled full installation within three days, well under the five-day target
- Reduced logistics & footprint: Clever stacking design meant the entire 560 m³ of tanks arrived on just three lorry loads, cutting transport-related CO₂ emissions and easing site congestion.
- Sustainability built in: The tanks are made from 100% recycled polypropylene, and fully recyclable at end of life.
M&J Evans Construction is a groundworks and civil engineering company operating as a sub-contractor major and regional housebuilders.
M & J Evans contracts manager Adam Newsome praised the system:
“The product is very easy to be delivered to site and store due to the ingenious stacking system … installation was quick and non-problematic … expertise and product support from Wavin representatives was second to none.”
This project exemplifies how engineered SuDS infrastructure, grey by nature, can deliver on green ambitions, comply with Defra standards, and, critically, accelerate housing delivery when sewer capacity is tight.
Unlocking homes, boosting resilience
The combined forces of grey infrastructure such as AquaCell NG and SuDS-aligned thinking can help overcome the severe sewerage bottlenecks stalling UK housing. When engineered systems are designed with multifunctionality and regulatory alignment at the fore, they become enablers rather than obstacles.
Housing projects across the country can learn from Worksop, tackling drainage constraints head-on with solutions that deliver sustainability, speed, and resilience. As professionals, we must embed these approaches into the earliest design conversations.
Let’s leverage Defra’s SuDS standards as catalysts for progress, not compliance tasks. By uniting engineered and green infrastructure, we can unlock thousands of homes, build climate-ready communities, and deliver long-term value for residents and ecosystems alike.
- Martin Lambley is senior product manager – urban climate resilience at Wavin
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