EWSC Project Reports

This EWSC report examines how low-water-use housing developments affect drinking water and sewer networks, helping inform future design standards for low-demand communities. While reducing household water demand supports water security and sustainable growth, lower flows can increase risks such as water stagnation, reduced water quality, sediment build-up, odour and sewer blockages.

Using Anglian Water models and household demand scenarios of 150, 100, 90 and 80 litres per person per day, the project found that lower demand reduces flows and velocities across both networks. Measures such as pipe downsizing or steeper sewer gradients can improve hydraulic performance but may also affect fire flow capacity, downstream connections and operational resilience.

The report concludes that there is no universal design solution for low-demand developments. Instead, future systems require case-specific, evidence-based and adaptable designs, supported by modelling, smart meter data, monitoring, updated standards and stronger collaboration between utilities, developers, regulators and designers.