The latest National Standards published in July 2025 emphasise that the highest priority for managing run off from new developments should be the collection of rainwater for non-potable uses. Collecting and using water where it lands. Wonderful news that this basic fact has been recognised and encouraged. Rainwater Harvesting Ltd have a sustainable solution on how this can be achieved effectively and economically. Fast flowing rainwater off the roof is collected via standard guttering and stored in an underground tank. This harvested water can be used for any non-potable application. This includes flushing toilets, washing machines, watering the garden and other outside applications. It really does not make any sense to flush toilets with drinking quality water. This takes significant pressure off the mains water supply and supports Part G (Water Efficiency) of the Water Regulations.
As part of a Sustainable Drainage System (SuDS) an even better solution is Rain Activ. The system is designed with extra capacity in the underground tank and so during heavy rain events excess stormwater is stored within the tank. The attenuated capacity is calculated with hydraulic design software which takes into account factors including geographical position, available roof collection area, 100/200 year storm events, climate change and desired peak discharge rates. The SuDS control outlet aperture controls the release of water with discharge rates as low as 0.05 litres/second and so preventing overwhelming the drainage network. If the water is also being used for non-potable applications the water level may not rise to the SuDS outlet level and therefore no discharge at all takes place. Rain Activ makes it significantly easier to meet the National Standards for the collection of the first 5mm of rainfall while supporting Water Regulations Part C (Flood Resilience)
Designed for the UK — By People Who Understand It
Founded in 2008, RainWater Harvesting Ltd is a family-run business based in Peterborough, designing and manufacturing complete rainwater harvesting systems for UK homes. The company began when the founders struggled to find a reliable system for their own home extension. Frustration turned into innovation — and soon a business was born.
Today, with tens of thousands supplied across the UK we offer comprehensive systems that include everything from tanks and filters to WRAS-approved mains water back up systems. Our award-winning Rain Director ensures compliance with water provider standards and planning regulations.
Using innovative design we have complete packages that are cost effective and simple to install. With individual tank sizes ranging from 1500 litres to 7500 litres we have a solution regardless of the size of the home. For multi home developments Rain Activ can form an integral asset to site management. As roof water is stored below ground the requirement for land for attenuation purposes can be greatly reduced. This can therefore be used for other amenities or larger plot sizes.
Complete systems start from £1700 ex VAT for a single plot development. A cost effective long term solution to compliance. Our team are available to discuss future projects to assist with planning applications. We offer CPD’s and technical support to professional and trade clients as well as a tank cleaning service to existing customers.
We have a permanent stand at the National Self Build and Renovation Centre in Swindon, SN5 8UB and on the 27th September 2025 there is a specific workshop on Rainwater Harvesting and Water Conversation. Tickets are free to attend and we would welcome the opportunity to chat about any future projects with planning or advice with installation of systems.
Why Water Reuse and Rainwater Harvesting are Essential for Every UK Home
From reducing water bills and enhancing property value to mitigating surface water flooding and supporting planning compliance, water reuse through rainwater harvesting offers numerous advantages.
As the UK’s water challenges intensify, installing rainwater harvesting systems is a proactive step towards sustainable, resilient homes.
Whether you’re a homeowner aiming to cut water costs, a developer meeting sustainability goals, or an architect committed to flood prevention, rainwater harvesting is a smart, essential investment in the UK’s water-efficient future. Start your water reuse journey today and contribute to a more sustainable UK.
It’s a win-win: efficient water use and effective flood mitigation — all in one solution.
For more information please visit www.rainwaterharvesting.co.uk