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Carat Indirect XL/XXL Rainwater Harvesting System 8500-26000 Litres

£4,642.01£12,215.03 inc VAT

The Carat XL/XXL In-Direct supply system is designed for WCs, washing machines, irrigation, and outdoor cleaning.


FREE Delivery by Tuesday, 28 May, 2024.


Protecting you


The Carat In-Direct XL/XXL supply system is designed to support WCs, washing machines, irrigation and outside cleaning purposes. Rainwater is collected from the roof of the property and is 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 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 for the system to repressurise turning the power off to the pump. From the header tank, the water is gravity fed to the WCs etc. It is all automatic, whenever there is a demand for water i.e. when the toilet is flushed the harvested rainwater will be gravity fed to the toilet from the header tank and then the header tank is topped up by the pump inside the underground tank. In periods without rainfall, the water level inside the underground tank will drop.

When the rainwater level is too low the pump will stop pumping harvested rainwater to the header tank. This in turn will result in the rainwater level in the header tank dropping. Inside the header tank there is a floating ball valve which controls the top-up of mains water in periods with no rain. This means that the system maximises the use of all available rainwater. If the system is to be used for garden irrigation, an outside tap should be installed on the pipework directly off the pump. A T-junction can be used to achieve this. This will mean that the garden tap is then being supplied by direct pump pressure. (NB: when the tank is low on rainwater there will be no mains water top-up to the outside tap.)

The Carat In-Direct XL/XXL is ideal for property owners looking to reduce their mains-water usage by substituting for rainwater instead.

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

  • Underground tank (choice of tanks available, sizes vary according to property type)
  • Telescopic lid (choice of telescopic lid available, depending on tank location)
  • Maxi tank dome, DN150 pipe connections
  • Filter (Filter Package 3 Optimax Pro Filter internal – DN150 supplied in accordance with type of tank)
  • Submersible pump
  • 20 gallon header tank
  • Floating suction set with fine filter and hose.
  • Black and green pipe 25m (25mm with fittings).
  • NB. 22,000L & 26,000L tanks have two access turrets and are supplied with two Maxi domes with DN150 connections and two lids of the loading you require

Supplied by Others

  • 150mm diameter duct pipe to contain; power cable for the pump, also bringing mains water to header tank as and when required
  • 150mm 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)
  • 150mm diameter pipe for overflow from the tank to mains drainage network

System Benefits

  • Simple & quick to install
  • Submersible pump supplies harvested rainwater on demand to the header tank where it is then gravity-fed to the WCs & washing machine
  • The header tank controls the operation of the system, supply of harvested rainwater and backup mains water to the WCs
  • Dual valve system within the header tank prioritises rainwater supply over mains water, maximising the use of all available rainwater to save on mains water consumption
  • Mains water switchover point is at a lower level in the header tank and becomes operational when rainwater is not available from the underground Platin tank
  • Mains water backup supply is not reliant on power supply or pump pressure and therefore guarantees the supply of water to WCs at all times

Product Dimensions, Levels & Weights

Carat Tank Dimensions & Weights (8500L – 26000L)

Carat 8500L Tank | Download
Carat 10000L Tank | Download
Carat 16000L Tank | Download
Carat 22000L Tank | Download
Carat 26000L Tank | Download

CARAT Tank Levels Mini Dome | Download
CARAT Tank Levels Maxi Dome | Download

Carat XXL a New Dimension | 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



Carat Garden Indirect XL / XXL | Download


Carat XXL a New Dimension | Download

Installation & Commissioning

These informative guides cover the following:

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


A rainwater harvesting system will cut your home’s demand for drinking water by up to 50% and therefore also protect the environment. But how much time do you have to factor in for operating and maintaining such a system? GRAF rainwater harvesting systems are designed so that only very few of the components need checking. This film shows which components need maintenance and how often. The intelligent components deliver perfectly clear rainwater with minimum maintenance effort, enabling you to save drinking water and time.

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.
Delivery times stated are from receipt of order/payment & may vary subject to tank size & stock availability.

  • Delivery lead time is 5-15 working days for tanks up to 10,000L in size, subject to stock availability.
  • Delivery lead time is 15-25 working days for tanks above 10,000L in size, subject to stock availability.
    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 up to 1200L are generally delivered by carrier strapped to a pallet for forklift off-loading.
    Tanks up to 7500L are generally strapped to a pallet for forklift off-loading.
  • Tanks 8500L & above are generally supplied with slings for off-loading.
    Please advise if there is restricted access to the site or special delivery instructions.

Additional Items