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Graf Carat Septic Tank

A low weight septic tank to be used together with a drainage field. Has a baffle to hold back the solids allowing them to break down over time.

Graf 400mm Extension Piece

  • Graf-extension-riser

SKU: G50076-83 Categories: ,


The Graf Septic Tank, like all septic tanks, uses a ‘mechanical’ way of cleaning your sewage waste so that solids are captured and only liquid is discharged

These Graf Carat septic tanks are divided into two by a partition wall known as a baffle. This baffle helps keep back the suspended solids in the primary chamber of the septic tank where they are trapped and can then break down into sludge over time. The effluent (liquid) flows into the secondary chamber and can then be discharged into a suitable drainage field.

The Graf Septic Tanks are available in the following sizes:

2,700l (max. 4 people) – on sale was £978

3,750l (max. 11 people)

4,800l (max. 18 people)

6,500l (max. 30 people)

Not sure what size Graf Septic Tank you need? Take a look at our guide on How to Size a Septic Tank.

Key Benefits

  • 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 as standard:

  • An injection moulded plastic Carat tank
  • A mini tank dome
  • A mini telescopic dome shaft suitable for pedestrian loading
  • Buffer

Options available:

Heavy Duty cover – vehicle loading up to 3.5t with a maxi tank dome (DN100 connection), composite plastic telescopic lid

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


10 years warranty on the tank

Offloading is the responsibility of the customer

Take a look under the ‘More Information’ tab above for documents to download.

For information on Drainage Fields take a look at the British Water Code of Practice (opens in a new tab).

Delivery is free of charge (at the manufacturer’s discretion) to much of mainland U.K.

Delivery charges may apply to areas of Scotland, Islands and Northern Ireland – contact us for up to date delivery charges for these areas.

People (Max.) Volume (litres) Length (mm) Width (mm) Height total (mm) Weight (kg)
Standard Cover 4 2,700 2,080 1,565 1,830-2,030 140
Heavy Duty Cover 4 2,700 2,080 1,565 2,150-2,450 180
Standard Cover 11 3,750 2,280 1,755 2,020-2,220 175
Heavy Duty Cover 11 3,750 2,280 1,755 2,340-2,640 215
Standard Cover 18 4,800 2,280 1,985 2,250-2,450 220
Heavy Duty Cover 18 4,800 2,280 1,985 2,570-2,870 260
Standard Cover 30 6,500 2,390 2,190 2,530-2,730 265
Heavy Duty Cover 30 6,500 2,390 2,190 2,850-3,150 305