A greywater recycling installer installs systems that collect lightly contaminated wastewater from baths, showers and washbasins, treat it to the appropriate standard and feed it back into toilet cisterns. Systems comply with BS 8525 and Water Regulations. Simple direct divert systems store bath and shower water for short periods; more complex biological treatment systems handle longer retention. A correctly installed system can save 30-45 litres per person per day and is increasingly specified in new builds targeting the optional 110 litre/person/day water efficiency standard under Part G.
What they do
- Site assessment - occupancy, water use patterns and pipework layout
- System selection - direct divert vs biological treatment
- Collection pipework from baths, showers and basins
- Filtration and UV or biological treatment unit installation
- Storage tank installation with mains top-up
- WRAS-compliant backflow prevention throughout
- Feed pipework to toilet cisterns
- Commissioning, labelling and maintenance handover
When you need one
A greywater recycling installer is needed when you want to reduce mains water consumption, achieve Part G water efficiency credits or meet planning conditions on new developments.
Typical costs (UK, 2025)
| System type | Typical cost |
|---|---|
| Simple gravity-fed divert system (1-2 bed) | £1,500 - £3,000 |
| Pumped direct divert system (3-4 bed) | £3,000 - £6,000 |
| Biological treatment system with storage tank | £6,000 - £12,000 |
| Commercial hotel or leisure system | £15,000 - £50,000+ |
| Annual service (filter change, UV lamp) | £150 - £400 |
Payback periods vary widely - typically 10-20 years for domestic systems, 3-8 years for high-occupancy commercial buildings.
Qualifications to look for
Water Regulations Advisory Scheme approval is essential - greywater systems require WRAS Type AA or AB backflow prevention to prevent any risk of contaminating the mains supply.
BS 8525-1:2010 covers direct reuse systems; BS 8525-2:2011 covers systems with treatment. Ensure any installer designs to the appropriate part for the system type.
Most reputable system manufacturers (Aquality, Reln, Graf, Graf Carat etc.) offer installer training and certification. Manufacturer-certified installers provide better warranty support.
How to find a reputable greywater recycling installer
Frequently asked questions
Is greywater safe to use for toilet flushing?
Yes, when correctly treated. Short-retention direct divert systems are safe for domestic use provided storage time is under 24 hours. Longer-retention systems require biological treatment to BS 8525. The system must include clear labelling and backflow prevention to prevent any cross-connection with the mains supply.
How much water does greywater recycling save?
Toilet flushing accounts for roughly 30% of household mains water use. A greywater system fed from baths and showers can substitute 50-70% of WC flushing demand, saving 30-45 litres per person per day. The actual saving depends on household size, occupancy patterns and system design.
What regulations apply to greywater recycling systems in the UK?
Systems must comply with BS 8525-1:2010 (direct reuse) or BS 8525-2:2011 (treated systems), and Water Supply (Water Fittings) Regulations 1999 for backflow prevention. In new builds, the system may contribute to Part G water efficiency compliance.