Wastewater treatment upgrades are key to meeting housing targets

Wilo UK’s Simon Oakes is urging policymakers to act now and deliver a national acceleration plan to upgrade wastewater treatment plants, as, without immediate investment in treatment capacity, the UK will not be able to unlock stalled housing developments or meet its target of building 1.5 million new homes.

Increasing wastewater infrastructure capacity must be prioritised to handle heightened flows from new developments, and the government, water companies and developers must work together to prioritise these upgrades according to Simon Oakes, Wilo UK’s water management expert.

Many wastewater treatment plants (WWTPs) are already operating at or beyond capacity, leading to overloaded networks, storm overflow reliance and rising pollution incidents. In 2023, water companies recorded over 3.6 million hours of sewage spills across England – the highest on record – highlighting the scale of system overload.

Simon commented: “The UK’s wastewater infrastructure is overstretched, with treatment capacity in many regions already limiting planning approvals for new housing.

“Several catchments are now classified as ‘flow‑constrained’, meaning new homes cannot be connected without upgrades to treatment works. Without intervention, wastewater capacity will become a hard stop on national housebuilding ambitions. We’ve already seen the impact in Northern Ireland, and last year, the Home Builders Federation revealed 30,000 homes were being blocked from being constructed due to not having enough wastewater treatment capacity to serve them.”

To solve the challenge, Simon is calling for accelerated investment in wastewater treatment upgrades, especially in improving capacity at existing WWTPs, to unlock stalled housing growth. He warns that without modernisation, the UK risks a systemic mismatch between housing policy and wastewater infrastructure reality.

“If we want to build 1.5 million homes, we must first ensure the wastewater network can cope. Right now, in many regions, it simply can’t,” Simon added. “Treatment plants are struggling with peak flows, storm events, and population growth. The data shows the system is already under immense pressure.

“Upgrading flow‑to‑full treatment capacity is one of the fastest, most cost‑effective ways to increase headroom at existing sites without waiting years for major civil works. Optimising hydraulic performance, improving pumping efficiency and reducing bottlenecks can immediately increase throughput and resilience.”

To show the scale of the impact, Simon highlights a recent upgrade for a major southern water company. By increasing throughput at one of its WWTPs from 500 to 800l/sec through the installation of three new screens, the site is now on track to save more than £500,000.

Simon and Wilo are urging government, water companies, and developers to work together on a national wastewater capacity acceleration plan. Without decisive action, the UK risks missing its housing targets and worsening environmental outcomes.

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