3750 Litre Deep Dig Graf Carat Underground Tank

£1,800.00 ex VAT

Graf Carat 3750 litre underground rainwater storage tank the largest Carat tank designed for installation below ground in commercial or residential premises

SKU: GF-372025 Category: Tag:


Graf Carat 3750 litre underground rainwater storage tank designed for installation below ground to serve commercial or residential premises.

Why buy this tank?

  • Store rainwater ready for use under your garden
  • Lifting kit not necessary – can be man-handled onto the site
  • Exceptionally strong but light two piece Duralen moulding
  • Time tested and backed by a 15 year manufacturer warranty
  • Tank construction allows for manoeuvre into less accessible locations -even though doorways
  • Components precision made for fast assembly
  • Buy if you want to build your own system – pumps, filters pipes

What do I get?

  • Big, strong 2 piece tank for fitting underground
  • Carat assembly kit including the seals
  • Pedestrian load cover and tank sleeve (green) Height 750-950 mm. Maximum tilt 5%. Child safety lock.
  • Optional upgrade to a Maxi sleeve giving an extra 100mm of adjustment
  • Optional upgrade to a vehicle load cover
  • Optional additional extension sleeve for even deeper sites

About the Tank and Graf

The Graf Carat tank is the largest tank of its kind in the world to be manufactured by injection compression moulding. This technique provides the tank with unbeatable stability and ensures that each component is produced with the highest accuracy. Graf have invested €20m in their factory near Freiburg for the Carat range, introduced in early 2007.

Like the Graf Hercules, the Carat comes in two halves so you can carry it through tight spaces even dorways.. (and so we can stack many of them on one pallet for bulk transport). A centering bolt on the tank flange makes assembly accurate. The quick knock-on connections and the patented seal laboratory tested for 25 years ensure there are no leaks between the two sections… and yet you can disassemble it if you like. The material used is a PE variant called Duralen.

Features Check:

  • Preferably for underground mounting (can be used above ground at owner’s option)
  • German manufactured, TÜV safety-tested
  • Patented quick connection (no screws required for mounting)
  • Permanently watertight: durably sealed thanks to solid profile sealing
  • Easy transport thanks to low weight and practicable size
  • Durably sealed thanks to solid profile sealing
  • See table for dimensions and weight

Connections for underground installation:

Holes are pre-cut in the turret or dome for connecting the filter inside the turret. We recommend use of British standard 110mm brown piping (more accurately 4.25 inches or 108mm external diameter) as supplied by builders merchants like Jewson, Wickes etc. If you are using 110mm piping between your roof’s downpipes and the tank, and between the tank and the drain or soakaway, then you have no worries about compatibility of pipe sizes.

Compare the Carat S Tank Sizes

Tank 2700 Litres 3750 Litres 4800 Litres 6500 Litres
Product Code 370001 370002 370003 370004
Weight 120 kg 150 kg 185 kg 220 kg
Length 2080mm 2280mm 2280mm 2390mm
Width 1565mm 1755mm 1985mm 2190mm
Height 1400mm 1590mm 1820mm 2100mm
Total Height 2010mm 2200mm 2430mm 2710mm
Half Height ie before assembly (for access) 700mm 790mm 910mm 1050mm

* The half height is a useful dimension if your site is at the back of a house and you have to get the tank through the doors of the house. The Carat is shipped in two halves with the turret separate. By tipping the half tank on its side you and a colleague can walk it through a narrow door. Your door width needs to be marginally wider than the half height shown.