For combined rainwater detention and rainwater harvesting

  • To guarantee retention of rainwater, a delayed drain is fitted in the channel with 0.05 to 2.0 l/sec. depending on the customer’s specifications and the retention or harvest volumes. In the event of heavy rainfall, the water level in the cistern rises above the max. water level (short term) and is drained into the channel at delayed speed using a floating drain choke.
  • This relieves the channel and the treatment works.
  • The water level can rise to the emergency overflow and sinks slowly back down again after the rain to the long-term max. water level. This rainwater can then be harvested.
  • We also construct and supply individual, special solutions.
  • Sizes between 3,000 – 10,000 l with corresponding retention volumes are possible.
  • This special type of rainwater harvesting is prescribed or subsidised in many communities. 

Advantages

Thought-out in every detail

Low installation depth
Low installation depth
Low installation depth

The minimal installation depth saves you time and money during installation.

Low weight
Low weight
Low weight

Tank installation made easy! The significantly lower weight of GRAF products compared to steel or concrete cisterns makes transport and installation easier.

Retention Plus
Retention Plus
Retention Plus

A combined retention/rainwater utilisation saves up to 50 % drinking water. The water can be used for garden irrigation, cleaning work and in the house also for flushing toilets and washing machines.

Ready for connection
Ready for connection
Ready for connection

With GARANTIA tank systems, the connection seals are already pre-drilled and lip seals are pre-assembled. This saves time and therefore costs during installation.

Low installation depth

The minimal installation depth saves you time and money during installation.

Low weight

Tank installation made easy! The significantly lower weight of GRAF products compared to steel or concrete cisterns makes transport and installation easier.

Retention Plus

A combined retention/rainwater utilisation saves up to 50 % drinking water. The water can be used for garden irrigation, cleaning work and in the house also for flushing toilets and washing machines.

Ready for connection

With GARANTIA tank systems, the connection seals are already pre-drilled and lip seals are pre-assembled. This saves time and therefore costs during installation.

Sizing

Volume [l]Length [mm]Width [mm]Height [mm]Weight [kg]order no.add to enquiry
3000245021001050185390312
5000289023001315255390315
7500360022501565385390324

calculated size Request for information

Technical details

Installation

max. earth covering [mm] (without groundwater, vehicle loading) 1200

Accessibility

Earth covering with loading capacity [mm] 700 - 1000
max. axle load [t] 2.2
max. vehicle weight [t] 3.5
max. vehicle weight with reinforced concrete slab [t] 60

Groundwater installation

Earth covering with groundwater installation [mm] 700 - 1200

Downloads

Accessory