The 8500 Litre Underground Water Tank from GRAF is a Carat XL tank for larger non-potable water storage jobs. It is a step up from the 6500 litre Carat S. Customers often use it to hold rainwater for flushing toilets and watering, process water on farms and commercial units, or a reserve of water for washdown.
Because the tank sits below ground it frees up space, keeps the water cool and dark to limit algae, and is protected from frost. The ribbed polyethylene body is light enough for a small excavator to lift in, yet strong enough for long term burial.
Key Features
- 8,500 litre capacity (approx. 1,870 gallons)
- Tough, lightweight GRAF Carat XL polyethylene construction
- Suitable for rainwater and all non-potable water storage
- Maxi telescopic dome shaft with 150kg pedestrian lid as standard
- Optional 3.5 tonne traffic lid for vehicle areas
- Can be connected to further tanks for extra storage
- 15 year manufacturer warranty and 50 year design life
Where an 8500 Litre Underground Water Tank Fits
At 3.5 metres long and just over 2 metres wide, the 8500 litre underground water tank fits within a typical garden or yard excavation. A roof of around 100 square metres can collect enough rain in an average UK year to refill it several times, making it a sensible size for a family home or small business looking to cut mains water use.
Specification
- Capacity: 8,500 litres
- Tank dimensions: 3500 x 2040 x 2085 mm (L x W x H, before dome shaft)
- Weight: 365 kg
- Colour: Grey / black
- Loading: Pedestrian as standard, vehicle with traffic lid
- Not suitable for drinking water
- Manufacturer: GRAF UK
Optional Extras
- Traffic Telescopic Lid 3.5 Tonne, for driveways and car parks
- Tank Alert EZ High Level Alarm, which gives an audible warning when the water level gets high
Delivery
We deliver free to UK mainland addresses. The tank arrives on a lorry, so you will need a way to offload it on the day. You can download the dimension drawing and installation guide from this page.




