The 3750 Litre Carat AA Eco-Plus Rainwater Harvesting System from GRAF supplies rainwater to your toilets, washing machine and outside taps from a Carat underground tank. At 3,750 litres it suits a three bedroom family home.
As a guide, British Standard BS 8515 suggests a tank of around 5% of the rain your roof collects in a year, which for the 3750 litre tank works out at a roof area of roughly 125 square metres. Used for toilets and laundry, it also holds around 18 days of supply for up to 4 people.
How the Carat AA Eco-Plus System Works
A filter cleans rainwater on its way into the tank. After that, a wall-mounted pump unit inside the building draws water out through a floating intake. For example, you can fit the unit in a utility room, garage or plant room, where it is easy to reach.
A mains back-up cistern sits at the base of the pump unit. When a float sensor in the tank detects a low level, mains water fills the cistern so your toilets and washing machine keep working. Since the pump is above ground, servicing is simple and nothing needs lifting out of the tank.
Key Benefits
- Lower cost route to whole-house rainwater use
- Pump above ground, so servicing is simple
- Mains back-up cistern keeps appliances working in dry spells
- Compact wall-mounted unit for a utility room or garage
- Supplies toilets, washing machine and outside taps
What’s Included
- 3,750 litre Carat underground tank
- Telescopic dome shaft with 150kg pedestrian lid
- Inlet filter
- Floating intake filter
- Overflow syphon
- Wall-mounted pump unit with mains back-up cistern
- Float sensor
Not Supplied
- 100mm duct pipe for the pump hose and cables
- 100mm inlet drainage pipe from the downpipes
- 100mm overflow pipe to a soakaway or surface water drain
- Electrical connection (a qualified electrician should carry this out)
Specification
- Capacity: 3,750 litres (approx. 825 gallons)
- Tank: GRAF Carat tank, a compact upright design that keeps the excavation footprint small
- Tank dimensions: 2280 x 1755 x 1590 mm (L x W x H, before dome shaft)
- Tank weight: 150 kg
- Loading: Pedestrian as standard, vehicle with the optional traffic lid
- Warranty: 15 years on the tank, 2 years on parts
- Not suitable for drinking water
- Manufacturer: GRAF UK
Optional Extras
- Traffic Telescopic Lid 3.5 Tonne, for driveways, yards and car parks
Delivery
We deliver the 3750 Litre Carat AA Eco-Plus Rainwater Harvesting System free to UK mainland addresses. The tank arrives on a lorry, so you will need to be able to offload it on arrival. In addition, drawings, data sheets and installation guides are available to download on this page.










