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  • Graf Carat S 1000 Gallon Cistern | 372002

Graf Carat S 1000 Gallon Cistern (1000 Gallon Underground Water Tank)

Call 817-246-4567 for Freight Quote

Product Description

Graf Carat S 1000 Gallon Underground Cistern with Pedestrian Manway, 14" Telescopic Riser and Childproof PE Lid.

Carat Tank Features:

• high-strength underground system
• two halves nest for transport and storage
• simple assembly with reliable gasket
• gray, non-potable polypropylene
• includes access system with telescopic riser
• inlet, outlet, vent through access system
• internal filter fits in access system
• can be fully emptied
• up to 48” burial depth with extension
• nests for shipping and storage - 5 tanks per pallet
• dome rotates, and accessway telescopes

• 1000 gal: 7'6”L x 6'6”W x 6'0”H, 330 lbs

Spec Sheet
Tank Brochure
Installation Instructions

Assembly Video

*NOTE: Riser Kit is included. Kit includes: 24” telescopic riser, lid, and gasket.

The Tank Guaranteed Not to Collapse When Empty*

  • 1000 Fully-usable gallons
  • Attractive Riser and Locking Lid Included
  • Car-bearing Option Available
  • Groundwater stable up to the top of the tank (below the dome and riser)

* When installed in compliance with manufacturer's installation instructions



Easy and safe assembly

  • The patented quick connection (illustrated in green), allows the Carat tank to be assembled without screws in only few minutes. Disassembly is possible at any time.
  • The first-class EPDM material used in the profile seals (illustrated in yellow), has been laboratory tested to last more than 25 years.
  • The centering bolt (illustrated in orange) assures the accurate and easy assembly of the two half shells preventing any leaks


More advantages

  • Variable burial depth: 30" to 42" in standard configuration even in groundwater up to the top of the tank
  • 70.9" maximum burial depth even in groundwater up to the middle of the tank using optional risers
  • Unique in the world! – a global innovation: unique manufacturing process produces the highest stability due to latest techniques
  • Unique fit accuracy of the components thanks to new production process
  • Consistent quality due to TÜV safety testing and production monitoring
  • Vehicle-bearing (with telescopic cast iron manway kit)
  • Groundwater stable up to the middle of the tank due to extremely rigid construction
  • Secure investment with market leading 15-year warranty
  • Made from high quality Duralene; easy to recycle
  • Can be expanded as required
  • 26" Manway opening



Flush with ground level (2 seals)
The Carat S underground tank has numerous seals to effectively stop dirt getting into the tank. This means that seepage water cannot get into the tank and, thus, dirt particles cannot contaminate the rainwater. The seals are in the intersection between the tank and the tank dome and between the tank dome and the telescopic dome shaft. All supply pipes connected to the tank dome are also sealed with five lip seals as standard.



  • The global innovation – the new tank generation of the Carat rainwater underground tanks have been specially developed for rainwater harvesting
  • Frost-proof installation underground
  • Groundwater stable up to the middle of the tank due to extremely rigid construction



The tank that turns its head for you

The GRAF Carat S underground tank has a rotating tank dome. The tank dome can be aligned with the connections independently of the tank – this makes installation much easier! All installation pipes are connected using the five standard lip seals. The Carat S telescopic dome shaft connects the system to the ground surface. The height of the tank can be smoothly adjusted to suit the local conditions and it can be tilted by 5°. The whole system is flush with ground level.


Logistical advantages of the Carat:

The Carat tank consists of two half shells which can be stacked on top of each other, allowing multiple tanks to be stacked on a single pallet for shipping. For example, it is possible to stack seven 1,000 gallon Carat tanks on a single pallet. This allows a standard 40 ft. shipping container to house a total tank volume of up to 34,000 gallons! The tanks' unique stacking feature directly reduces transport costs and environmental impact from vehicle emissions.

Available Options:



Optional Optimax Pro® Internal Filter Package

Includes Optimax Pro Internal filter kit with calming inlet, overflow siphon and spannfix connection sleeve.

Graf Carat Tank Optimax Pro Internal Filter Package

Graf Carat Optimax Internal Filter Package

Graf Carat S Calming Inlet




Vehicle Loading Option - $689.95

Includes heavy duty telescopic dome shaft and cast iron lid for vehicle loading up to a maximum axle loading of 2.2 tons.

More Details:

The Carat is a high-strength underground tank built from two half-sections that are joined in the field with a reliable gasket and clamping system. This design makes it possible to transport a tank to the job site in a small truck, and then hand-carry the components to the excavation. A swiveling top compartment called a dome provides ample space for inlet, outlet, and filtration components. A telescopic riser slides into the dome and provides height adjustment so that the access lid can be positioned flush with the ground surface.

Carat tanks can be fully emptied for long periods without danger of collapse. With an extension and a heavy-duty riser, they can be buried up to 48” below grade; with a heavy-duty riser and a cast-iron lid they can be used under residential driveways and parking areas.

Other Details

7' 6"
6' 6"
6' 0"
Tank Material:
Black, injection-molded polypropylene
Tank Color:
Warranty Period:
15 yr manufacturer warranty

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