overflow syphon odour prevention
floating intake vavle
Minimax_Optimax Filter
Carat Direct Rainwater Harvesting System Scene
carat direct supply system

Carat Direct Rainwater Harvesting System 2700-6500 Litres

£2,539.12£3,181.94 inc VAT

The Direct-supply system is designed to support WC’s, washing machines, irrigation and outside cleaning purposes.


FREE Delivery by Tuesday, 21 May, 2024.


Protecting you


How does the Carat Direct Rainwater Harvesting Package work?

Rainwater is collected from the roof of the property and fed into the underground tank via the downpipes. On entry to the tank, the water passes through a filter to prevent any debris from going into the tank. With this system, there is a mains water top-up unit located within the property.

This unit supplies mains water to the underground tank when the rainwater level is low. The operation of this unit is controlled via a float switch. There is a pressure-sensitive pump located in the underground tank. When a valve or tap is opened, water will be pumped under pressure until the valve is closed, allowing the system to repressurise turning the power off to the pump.

Why choose the Carat Direct Rainwater Harvesting System:

  • Economical Gravel Backfill: Unlike traditional concrete-based systems, our gravel backfill approach can save you an impressive £60 per cubic metre in installation costs.
  • Flexible Installation Options: With its vehicle loading lid, the system can be installed under driveways, offering a space-saving solution for homes with limited garden space.
  • Eco-Friendly Construction: The underground tank is made entirely from 100% recycled plastic, emphasising our dedication to sustainability.
  • Proven Quality: As a product from a European market leader, you can trust the reliability and effectiveness of this system.
  • Effortless Operation: The automatic submersible pump comes with automatic restart and dry-run protection, ensuring a seamless and low-maintenance operation.
  • Continuous Water Supply: Unique to this system is its integrated mains water back-up. When rainwater levels are low, the system automatically tops up the underground tank with mains water, ensuring you always have a water supply.


Images are for illustrative purposes only; there is a possibility that certain products may have been upgraded or replaced with equivalent alternatives.

What’s included

Supplied by Graf

CARAT complete package Direct-Supply 2700-6500 litres, comprising of:

  • CARAT underground tank 2700-6500 litres, without dome
  • CARAT tank dome Maxi black, with sealing set DN 100
  • CARAT telescopic dome shaft Mini green, with PE-lid, for pedestrian loading/or vehicle loading
  • CARAT Filter package 3 House, Optimax-Pro filter internal/inflow stilling system/overflow siphon/Spannfix – DN 100
  • Pump package Home Direct Carat
  • Mains water back-up unit
  • Float sensor (connected from mains water back-up unit to the underground tank)

Supplied by Others

  • 100mm diameter duct pipe to contain; float sensor cable, power cable for pump, also bringing mains water to underground tank as and when required
  • 100mm diameter drainage pipe connected from downpipes to the inlet at the top of the tank (all downpipes brought into one pipe for connection to the filter)
  • 100mm diameter pipe for overflow from the tank to mains drainage network

System Benefits

  • Simple & quick to install
  • The submersible pump supplies harvested rainwater on-demand to WCs, washing machines & external tap
  • Mains water back-up unit tops up the water level in the Carat tank when rainwater levels are low to guarantee continued water supply
  • The quiet & conveniently sized mains water back-up unit will fit in a kitchen or utility cupboard for very low visual impact
  • Innovative float sensor detection on the mains water back-up unit ensures that the underground tank is kept supplied with mains water but only the amount necessary to maintain supply to toilets and washing machines, leaving as much volume as possible in the tank to collect rainwater when available

Product Dimensions, Levels & Weights

Carat Tank Dimensions & Weights (2700L – 6500L)

Carat S 2700L Mini | Download
Carat S 2700L Maxi | Download
Carat S 3750L Mini | Download
Carat S 3570L Maxi | Download
Carat S 4800L Mini | Download
Carat S 4800L Maxi | Download
Carat S 6500L Mini | Download
Carat S 6500L Maxi | Download

CARAT RS-Series Installation and maintenance instructions | Download
CARAT Tank Levels Mini Dome | Download
CARAT Tank Levels Maxi Dome | Download

Mini & Maxi Lid Dimensions

PE Mini Lid (Pedestrian Loading 371010) | Download

PE Maxi Lid (Pedestrian Loading 371011) | Download

Vehicle Loading Lid (371052) | Download

Extension piece options

Extension Sleeve (371003) | Download

Extension Sleeve (371015) 1000mm | Download



GRAF Carat S RWH Brochure | Download

Data Sheets

Carat House Direct Package | Download


Carat Direct Schematic Layout | Download

Installation Instructions

Home Direct System Installation Manual | Download

Installation & Commissioning

This informative guide covers the following:

  • Loading information
  • Tank coverage heights
  • Excavation dimensions
  • Technical & general data
  • Installation & Assembly

Read the Guide | Download
Read the Guide (Tank Only) | Download

Service Provider Support

Graf UK has a national service provider network of contractors who can offer various services including the installation of our tank systems.

Coming Soon:
New UK map with the service provider/installer contact details.

Delivery Information

Please note the following regarding Graf UK deliveries

We’re still delivering to our customers safely via our own delivery vehicles & drivers in the main, using external hauliers when required.


This gives us much greater control & flexibility over our deliveries.


All orders are typically delivered within 5-7 working days from receipt of order, however during this time due to UK-wide disruption, some deliveries may take a little longer and we would still aim to deliver within 10 days.

• Delivery lead time is 5-7 working days on all orders unless otherwise advised.
• Price includes delivery to mainland UK.
• Please check for deliveries into Cornwall, Mid & Northern Scotland & Isles as additional delivery charges may be applicable.
• We cannot currently provide a tracking number for all orders but can accept customer enquiries by phone.
• Off-loading by the customer unless agreed otherwise.
• Tanks are generally strapped to a pallet for forklift off-load, slings can also be used.
• Please advise if there is restricted access to the site or special delivery instructions.

Additional Items