IN Brief:
- GRAF UK has launched a refreshed AA rainwater harvesting range for non-potable building uses.
- The systems use underground tanks made from 100% recycled plastic in capacities from 1,500 to 7,500 litres.
- The design feeds mains backup directly into building plumbing, preserving tank capacity for collected rainwater.
GRAF UK has launched a refreshed AA rainwater harvesting range for buildings, using underground recycled plastic tanks and a mains backup arrangement designed to preserve full tank capacity for collected rainwater.
The range includes AA Eco-Plus and AA Silentio systems, with tanks available from 1,500 litres to 7,500 litres. The systems are intended for non-potable uses such as toilet flushing, washing machines, garden irrigation, and external cleaning, allowing buildings to reduce demand for treated mains water where potable quality is not required.
Instead of feeding top-up water into the underground tank, the AA system supplies mains water directly into the building’s plumbing circuit when rainwater levels are low. That arrangement preserves the tank’s capacity for harvested rainwater and avoids displacing stored water with mains supply.
The systems use a Type AA air gap arrangement to support compliance with the Water Supply (Water Fittings) Regulations 1999. The physical separation between mains water and harvested rainwater protects the supply network while allowing automatic switching when rainwater availability falls below the level required for operation.
Rainwater harvesting has moved from a niche sustainability option into a more practical building services consideration. Water scarcity, flood resilience, and utility costs are becoming more visible in design and refurbishment decisions, while developers and building owners are under growing pressure to reduce demand on public infrastructure.
Non-potable demand can be significant in commercial, residential, education, healthcare, and public-sector buildings. Toilet flushing, cleaning, landscape irrigation, and laundry loads create regular opportunities to substitute harvested water for mains supply, provided systems are reliable, easy to maintain, and compatible with building operation.
The use of recycled plastic tanks also places the range within the wider circular construction agenda. The sector’s shift toward reuse, lower waste, and longer product life has already been reflected in construction circular economy work linked to refurbishment, and building services products are increasingly being assessed through the same whole-life lens.
Installation practicality will influence uptake. Underground tanks can be easier to justify on new-build sites where groundworks are already planned, while refurbishment and renovation projects often face tighter limits around excavation, drainage integration, and access. Shallow installation tanks and modular system options can reduce some of those barriers, particularly where external works are already part of a project.
Lower-resource building technologies are now being judged on operational performance rather than environmental claims alone. Rainwater harvesting systems have to work quietly in the background, switch reliably to mains backup, maintain water quality, and avoid creating additional maintenance risk. Where those conditions are met, the technology can become a standard part of water-conscious building design rather than a discretionary sustainability feature.
