Posted by Callum Vallance-Poole, on September 13, 2024.
North West Bicester in Oxfordshire is home to the UK’s first eco town, featuring 91 true zero-carbon homes. To meet Code for Sustainable Homes Level Five standards, developer A2Dominion aimed to limit potable water consumption to 80 litres per person per day. Ensuring effective flood protection was also crucial. To achieve these goals, they enlisted the expertise of civil engineering consultancy Infrastruct CS Ltd. to specify an efficient water management solution.
Infrastruct CS Ltd. partnered with Graf UK to design, install, and commission a comprehensive rainwater harvesting and stormwater management system for each of the 91 properties. This solution included a 1,500L Platin rainwater harvesting tank and a soakaway system using Rain Bloc stormwater attenuation modules. These modules channel stormwater into a central soakaway, where water is gradually released into the ground, reducing drain pressure and mitigating flood risks. The Rain Bloc crates have a lorry-bearing capacity of 60 tonnes with a 500mm earth covering. Weighing just 19 kilograms, they are easy to install and connect quickly using simple connectors.
The rainwater harvesting systems are seamlessly integrated into each home. The Platin tanks are installed underground and equipped with submersible pumps that transfer collected rainwater to a header tank in the loft. This water is then gravity-fed to the bathrooms, where it is used for sustainable toilet flushing. The stormwater management system, consisting of Rain Bloc crates, efficiently controls water release into the underlying ground.
Graf UK’s rainwater harvesting and stormwater management systems are now operational in all 91 homes, helping achieve the stringent Code for Sustainable Homes Level Five standards and significantly reducing flood risk. The systems ensure minimal use of mains water, resorting to it only when rainwater tanks are empty, thus saving water and reducing utility bills for homeowners and tenants.
Tim Trotman, Director at Infrastruct CS Ltd, shared his satisfaction: “The system is engineered to use hardly any mains water, only diverting to the mains supply if the tank is empty (for example, after a particularly hot, dry spell). This not only helps save water but also keeps bills down for homeowners and tenants. Graf UK is a company that’s local to us, and we’ve worked with them several times before, so we knew they could help us find the right water-saving solution to meet the needs of this unique project.”