Rainwater on demand, with mains backup built in
The Platin AA Eco-Plus system collects the rain that falls on your roof, stores it in an underground tank and supplies it on demand to your toilets, washing machine and outdoor taps. It’s a complete package for homeowners, self-builders and installers: tank, filter, floating intake and pump unit, chosen to work together.
How it works
Rain runs from your downpipes into one pipe and into the tank. On the way in, it passes through a Minimax filter that keeps leaves and debris out. Inside the tank, a floating intake draws water from just below the surface, so only the cleanest water is used.
The AA Eco-Plus pump unit sits above ground inside the property. When you flush a toilet or open a tap, it draws rainwater from the tank and supplies it to your home. Because the pump is above ground rather than in the tank, servicing and upkeep are simple.
Automatic mains backup that keeps the tank for rainwater
The AA Eco-Plus unit has a built-in mains water cistern. If rainwater in the tank runs low, the system switches to mains water from the cistern, controlled by a float switch, so your home is always supplied and uses only the mains water it needs. Mains water never goes into the underground tank, so the whole tank stays available for rainwater.
What the AA air gap does
UK water regulations require a physical break between harvested rainwater and the mains supply. The AA Eco-Plus unit has an AA air gap: a gap of open air between the mains water inlet and the water in the cistern, so rainwater can never flow back into the mains pipe. It keeps your household supply safe and compliant with water regulations. Read more: What is an AA air gap in a rainwater harvesting system?
AA Eco-Plus or AA Silentio?
Both systems use the same tank, indoor pump unit, mains backup cistern and AA air gap. The AA Silentio package adds a reversible flow filter, a water level sensor in the tank and a jet wash feature for the tank filter. Compare them in our guide: AA Eco-Plus vs AA Silentio: which rainwater harvesting system is right for you?
Choose your size
The Platin is a shallow-dig tank: it’s wide and low rather than tall, so it needs a shallower hole than a traditional upright tank. It’s made from 100% recycled plastic and is installed with gravel backfill rather than concrete, which makes installation simpler and saves around £60 per cubic metre. Platin tanks are trusted across Europe for their reliability in rainwater harvesting.
| Capacity | Length | Width | Height to tank shoulder |
|---|---|---|---|
| 1,500 litres | 2,100mm | 1,250mm | 700mm |
| 3,000 litres | 2,450mm | 2,100mm | 735mm |
| 5,000 litres | 2,890mm | 2,300mm | 1,000mm |
| 7,500 litres | 3,600mm | 2,250mm | 1,250mm |
All sizes have a 315mm dome collar. Choose a pedestrian lid for lawns and garden areas, or a vehicle lid if the tank will go under a driveway.
Useful links
- Want extra filtration and a tank level sensor? See the Platin AA Silentio system
- Need a taller tank with a smaller footprint? See the Carat AA Eco-Plus system (2,700–6,500 litres)
- Add a Digital Level Indicator to see how much water is in the tank
- Tank going in deeper? Add an Extension Piece
- See how the system fits together: How rainwater harvesting systems work: the AA system explained
- Not sure which system you need? Read our guide: Comparing rainwater harvesting systems: direct, indirect and garden-only
- Work out the right tank size with our rainwater harvesting tank size calculator
Images are for illustration; components may be upgraded or replaced with equivalent alternatives.
