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Carat 2700L-6500L Underground Water Tank

Delivery: 7-10 working days

£1,238.74£1,848.59 inc VAT

CARAT range of underground tanks are suitable for use with the following applications:

  • Non-potable water
  • Wastewater
  • Raw sewage
  • Effluent
  • Silage
  • Slurry
  • Rainwater
  • Grey water & blue water
  • Cesspool
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Description (click to expand to read)


Carat 2700L-6500L Range:

CARAT tanks are supplied fully assembled.

Carat 2700L-6500L Underground Water Tank 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 PP cover suitable for vehicle loading
  • Additional inlet/outlet, with sealing set DN 100, can be core drilled into the shoulder of the tank
  • Multiple tanks can be connected to increase storage capacity if required, with low-level connections with sealing set DN 100.

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 water tank & dome (choice of tanks available, sizes vary according to application type).
  • The pedestrian telescopic lid as standard, 3.5 tonnes vehicle loading adjustable lid available on request.
  • Extension pieces (risers) as required (extra over items).

Supplied by Others

  • Inlet/outlet drainage pipework
  • Connecting pipework between multiple tank systems

System Benefits

• Simple & quick to install
• High quality, robust, polypropylene tank & related accessories for use with a wide range of media
• Adjustable lid height for flush alignment to ground level
• Pedestrian telescopic lid as standard, 3.5 tonnes vehicle loading adjustable lid available on request
• Fully compatible tank domes, risers & lids to deal with invert level requirements
• All tank dome, riser & lid connections include a high-quality thick rubber gasket for watertight seals
• Granular or concrete backfill options, subject to ground conditions & groundwater level

Product Dimensions, Levels & Weights

Carat Underground Water 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


Carat S underground water tank | Download
Carat Tank (Levels, Maxi Dome) | Download
Carat Tank (Levels, Mini Dome) | 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

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 fork lift off-load, slings can also be used.
• Please advise if there is restricted access to site or special delivery instructions.