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Graf Carat Underground Storage Tank

The perfect solution for the waste product or rainwater storage


Graf 400mm Extension Piece

SKU: G70021b Categories: ,


The Graf Carat Underground Storage Tank is manufactured by injection compression moulding which provides unbeatable stability.  Unlike other underground tanks, the wall thickness is equal in all areas of the tank.

GRAF Carat RS tanks are made out of 100% post consumer plastic waste.

These tanks are available in the following sizes:





GRAF Carat RS tanks are made out of 100% post-consumer plastic waste.

Key benefits:

  • It has a rotating tank dome which can be aligned with the connections independently of the tank
  • Sealed up to ground level
  • The tank has a ribbed base and is extremely stable
  • Can be installed easily using a gravel backfill which means much easier and cheaper installation costs
  • Low weight: can also be installed in difficult local conditions without a crane
  • Low maintenance: maintenance or cleaning work can be performed through the shafts
  • Tanks can be used as rainwater harvesting systems after thorough cleaning

This kit price includes:

  • An injection moulded plastic Carat tank
  • A maxi tank dome with connection DN100
  • Mini telescopic dome shaft suitable for pedestrian loading


10 years warranty

Options available:

Heavy Duty cover – vehicle loading up to 3.5t with a maxi tank dome (DN100 connection), cast iron telescopic dome shaft

Neck Extension – working height 305mm (total height 400mm)

Offloading is the responsibility of the customer

Volume (litres) Length (mm) Width (mm) Height total (mm) Weight (kg)
Standard Cover 2,700 2,080 1,565 2,105-2,350 129
Heavy Duty Cover 2,700 2,080 1,565 2,105-2,450 175
Standard Cover 3,750 2,280 1,755 2,340-2,540 159
Heavy Duty Cover 3,750 2,280 1,755 2,340-2,640 205
Standard Cover 4,800 2,280 1,985 2,570-2,770 194
Heavy Duty Cover 4,800 2,280 1,985 2,570-2,870 243
Standard Cover 6,500 2,390 2,190 2,850-3,050 229
Heavy Duty Cover 6,500 2,390 2,190 2,850-3,150 275
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