


- Description
GRAF Carat S 3750L Eco Plus Rainwater Harvesting System
The GRAF Carat S 3750L Eco Plus rainwater harvesting system captures rainwater from your roof, filters it and stores it in a durable underground tank, ready to be reused around the home and garden. A complete GRAF system can cut mains water use by up to 50%, lowering bills and easing pressure on the public supply. With 3750 litres of storage, this configuration suits family homes of 4 to 6 people served by a medium to large roof area.
Eco Plus complete home package
The Eco Plus is a complete, cost-effective whole-house package that pairs the underground tank with an external filter and a submersible pump. It supplies WCs, washing machines and garden taps, helping cut mains water use without a premium price tag.
Why choose the GRAF Carat S tank
The GRAF Carat S is a high-strength round tank with a rib-reinforced body and a load-bearing telescopic dome, giving proven durability and flexible installation depth for domestic and light-commercial sites. The tank is moulded from lightweight, high-strength polypropylene, so it is easy to handle on site yet built to last. A telescopic dome shaft adjusts to suit your ground level and can be specified with pedestrian or vehicle-rated covers.
Key features
- 3750L underground storage capacity
- Reduces mains water consumption by up to 50%
- Lightweight, corrosion-resistant polypropylene tank
- Height-adjustable telescopic dome shaft
- Complete, value-focused whole-house harvesting kit
- External filter with submersible on-demand pump
- Automatic mains top-up keeps supply constant
- Quick installation on a gravel base with granular backfill
Applications and Usage
This system is well suited to domestic new-builds, self-builds and retrofit projects where reducing mains water use is a priority. Harvested rainwater is perfectly suited to WC flushing, washing machines, outdoor taps and garden irrigation - typically over half of a household's daily water demand. Specifying rainwater harvesting can also support SuDS objectives and planning requirements by attenuating roof run-off on site. Installation is straightforward: the tank is bedded on a gravel base and surrounded with granular backfill, avoiding the cost and effort of a concrete surround on most domestic sites.
Learn more about GRAF products here.
- Delivery
There may be an additional charge for delivery of items outside UK mainland and offshore addresses; under these circumstances, please contact us for an updated quote on delivery before placing your order. Further payment may still be required for larger items – Please get in touch with us and we can arrange an updated invoice to reflect this. Your purchase with us will be held and stock allocated.
This includes Scotland, the Highlands and Islands, Northern Ireland, the Isle of Wight and the Isle of Man.
Postcodes including (but not limited to) DD, PH, IV, KW, HS, AB, PA, KA, ML, EH, KY, FK PO (PO – Isle of Wight) and G.
If access to the delivery address is restricted, please advise when placing the order. This will allow us to arrange for a suitably sized delivery vehicle. The customer is responsible for arranging for large items to be offloaded from the delivery vehicle at the customer’s premises. Please allow up to 10 working days for delivery.
Our suppliers arrange delivery at the source, so carriage charges may vary based on your postcode. We will happily provide you with a delivery quote; just call us on 01722 442446.
Next-Day Delivery is not Guaranteed – The order Cut-off for Qualifying next-day delivery addresses is 3pm. But please contact us as some orders can still be fulfilled after this time.
- Returns Policy
In accordance with United Kingdom and European law, customers have an unconditional right to cancel an order for a full refund from Tank Services up to 14 days after the goods are received by you.
If a customer wishes to return an item and cancel an order with Tank Services, please contact us within the period outlined above to arrange for the goods to be returned at cost to you. It is not Tank Services’ responsibility to pay for the return of your goods (see T&Cs for more information ).
Please take care when ordering the correct product, as the cost of returning tanks and bulky goods can be expensive.
It is the customer’s responsibility to ensure that good care is taken of the goods whilst in their possession. Goods must be returned to Tank Services in a suitable resale condition and unused as determined by the Supplier. Please see our standard Terms & Conditions for further details.
For BUSINESS Customers & Bespoke items; any refund will be less an administration fee of 20% + VAT of the total order value.
GRAF Carat S 3750L Eco Plus Rainwater Harvesting System
GRAF 3750L Carat S Eco Plus Rainwater Harvesting System suitable for both household and outdoor use.
- Enquire About Stock or Availability
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