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GRAF Carat-S Rainwater Tank.
  • GRAF Carat-S Rainwater Tank.
  • GRAF Carat-S House Direct Rainwater Harvesting Package.
  • GRAF Carat-S House Direct Rainwater Harvesting System.

2,700 litre GRAF Carat S House Direct Rainwater Harvesting System

10-14 working days
10-14 working days
£1,548.93 ex. VAT

Product Details

This item is supplied to order and additional refund & returns terms apply.


Tank Type: Deep Dig
Capacity: 2,700 litres
Length: 2080mm
Width: 1565mm
Height: 2010mm
Inner Ø dome shaft: 650mm
Tank Weight: 120kg
Dome Shaft Weight: 9kg (pedestrian loading)/55kg (vehicle loading)
Warranty: 15 Years

This 2,700 litre Carat S House Direct Rainwater Harvesting system from GRAF is designed to be a simple domestic solution. Quick and easy to install, it has a submersible pump which supplies harvested rainwater on demand to toilets, washing machines and external tap. It also features a Mains-on-Tap unit that tops up the tank whenever rainwater levels are low, guaranteeing a continued water supply.

Product Features at a Glance:

  • Simple & quick to install
  • On Demand Rainwater Supply - submersible pump supplies harvested to toilets, washing machine & external tap.
  • Guaranteed Water Supply – tank topped up with mains supply when water level in the tank is low.
  • Mains-on-Tap - quiet and conveniently sized unit that can fit in a cupboard for low visual impact.
  • Innovative Float Sensor - ensures underground tank is kept supplied with mains water, but only the amount needed to supply demand whilst leaving as much volume as possible to collect rainwater when available.

Customer Notice: The processed water may be used to water the garden, flush toilets, wash clothes and as conventional cleaning water. It is Not suitable for consumption or personal hygiene.

GRAF Carat S Household Rainwater harvesting packages feature their patented Optimax-Pro (self-cleaning) filter that requires minimum maintenance and provides over 95% water yield. The filter housing has a transparent lid for filter visibility and can be easily removed without tools.

The complete system includes:

1 x Carat underground tank
1 x Mini telescopic dome shaft with PP cover (pedestrian loading)
 or Cast iron telescopic dome shaft with childproof cover (vehicle loading up to 3.5 ton)
1 x House filter package consisting of:

    • Internal Optimax-Pro (self-cleaning) filter
    • Inflow stilling system for controlling the water inflow
    • Overflow siphon with rodent guard function
    • Spannfix pipe connection sleeve

1 x House Direct pump package consisting of:

    • Mains on tap
    • INOX submersible pump
    • Internal Hose connection box
    • Floating suction set with fine filter and hose
    • Black and green pipe 25m

The Carat tank series are the foundations of a long-lasting rainwater harvesting system. Manufactured by injection compression moulding, these tanks boast unbeatable stability with each component produced to the highest accuracy. The tank dome can be rotated 360° and sits on a telescopic, inclinable shaft allowing it to be easily aligned to connection pipes and installed flush with the soil level. Add to that its intelligent filter components and you have an easy to install system that ensures the best quality from your harvested rainwater. 

For more information about rainwater harvesting, and advice on how to choose a system and tank size, take a look at our supporting articles here.

Key Features of Carat House Direct Tanks:

  • Self-cleaning filter - the patented Optimax-Pro self-cleaning filter delivers a water yield of over 95 % and requires minimal maintenance.
  • Very high water quality - floating extraction unit extracts the water from the cleanest zone – about 10 cm (4") below the water's surface.
  • Dome shaft - provides easy access to the filter and tank, can be fitted with covers suitable for either pedestrian or vehicle loading.
  • Versatile Tank Cover - can be telescoped and tilted in a continuously variable manner and blends seamlessly into the ground surface.
  • Suitable for Vehicle Loading - when combined with a cast iron telescopic dome shaft, meaning the Carat tank can then be installed under your driveway.


Please Note: All dimensions are approximate (the manufacturer reserve a tolerance of +/- 3%) and the useful volume of the tanks may be up to 10% lower than the tank capacity, according to the connecting option. All images shown are used for illustration purposes only and may differ from the actual product supplied.

Disclaimer: Pre-condition for warranty benefits are proper handling, assembly and installation according to the mounting guidelines. The warranty may become invalid if any of these conditions are breached.

10-14 working days
Install Type:
Below Ground
Product Type:
Deep Dig
1000 - 5000 litres
Water Supply: