Graf Carat S 700 Gallon Cistern

Graf Carat S 700 Gallon Cistern
Free Shipping

Graf Carat S 700 Gallon Underground Cistern with Pedestrian Manway, 14" Telescopic Riser and Childproof PE Lid.

Our Price$1,969.95
List Price$2,364.00

Contact us for current lead time.

Upgrade to a Complete System and SAVE!
In Ground System or IGS Collection System

  • 1.25 HP Pump
  • Automatic Controller
  • Graf Optimax Filter
  • Floating Extractor
  • Overflow Siphon
  • Calming Inlet
  • 1.25" Bulkhead Fitting
  • In-Ground First Flush Kit
  • Miscellaneous Fittings
Add to Cart

The Tank Guaranteed Not to Collapse When Empty*

  • 700 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 five 1,700 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.

How to Assemble a Carat Tank Video:

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.

Tank Documents:

Graf Carat Tank Specifications

Download Graf Carat Tank Spec Sheet

Download Graf Carat Tank Installation and Maintenance Manual

Graf Carat Tank Assembly Video

View Video of Carat Tank Assembly

No recommended products at the moment.
No recommended products at the moment.