WISY storm water retention tanks offer an additional retention volume with throttled outlet in addition to the useful volume for rainwater harvesting. The total tank volume is 5.5 m³ including a retention volume of between 1.5 and 2.5 m³. The retention volume and outlet must be selected according to urban land use planning guidelines.
The WISY storage tank is optimally shaped to withstand vertical compressive loads. The rainwater storage tank is a seamless one-piece unit for long-term leak-tightness. We offer a 20-year guarantee on the durability of the environmentally friendly polyethylene tank material.
Thanks to their exceptional strength, WISY storage tanks with a steel cover are capable of withstanding the weight of passing road vehicles. This means that they can be installed under the driveway as well as in the garden. Even when weather conditions are wet, the non-slip cover is safe to walk over.
In contrast to the non-slip tank cover, the inside tank walls are perfectly smooth. This feature helps to prevent buildup of deposits and creates the best possible environment for maintaining water of optimum quality.
Thanks to their light weight and two rugged lifting eyes, WISY storage tanks are particularly easy to handle on site (using a mini-digger, for example). When the excavated pit is filled up with gravel the storage tank is fully supported from below. Tube bushings with fitted seals make installation even easier. For additional safety, a compressed water equalizing valve is fitted in the tank base for protection in the event of groundwater collection around the tank. The wide access shaft ensures ease of entry for maintenance work.