Design Solution · Water Management
Design Solution · Dream about it
Harvest rainwater and recycle treated greywater for non-potable uses.
Rainwater is harvested and greywater (and in some schemes blackwater) is treated on site and recycled for non-potable uses such as WC flushing and irrigation, cutting mains water draw. Storage, cleansing biotopes and smart irrigation extend the captured supply.
Harvesting rainwater and treating greywater for WC flushing and irrigation is a well-understood water efficiency strategy that has been deployed on certified sustainable buildings for two decades, making the core concept much more established than its zero-evidence record here would suggest. The value case is strongest on large-footprint buildings with high non-potable demand — offices, schools, hotels — where the volume of flushing and irrigation justifies the collection and treatment infrastructure. Greywater treatment introduces an ongoing operational commitment: biological treatment systems require maintenance and periodic disinfection, failure modes affect water quality rather than just efficiency, and building operators frequently lack the skills or motivation to manage them correctly after handover, which has been the most common failure mode in documented UK installations. Regulatory acceptance for on-site blackwater treatment remains limited in most UK local authority jurisdictions, so schemes typically stop at greywater and rainwater, limiting the fraction of total demand that can be offset. The design team's risk is over-specifying collection capacity relative to the available catchment area and non-potable demand profile, producing systems that are expensive to run relative to mains water savings — size it from a realistic demand model, not an aspiration.
#greywater #rainwater harvesting #water reuse #irrigation