Monthly Archives: March 2019

Have You Experienced Flooding? You May Need A Detention Tank

If you are building a new home, there may be several requirements that you’ll need to meet. One of these requirements might be stormwater management, which will require the use of a detention tank. If you are experiencing flooding, a detention tank may also be your answer.

What are detention tanks?
Detention tanks are large tanks that are normally installed below the surface and used to suppress the effects of heavy rainfall, or stormwater. They work by temporarily storing the rainwater runoff during rainfall and slowly release the water through a small diameter orifice into the public storm water system. This reduces the peak flows of stormwater and reduced the chance of flooding due to an overloaded stormwater system.

Detention tanks are usually required in areas where storm water flooding risks are high. This is especially true in many areas in Auckland, with the current increase in population and housing. Generally speaking, if you are adding roof space by extending or building a new home in areas where stormwater systems have not been renewed, you will most likely require a detention tank.

Detention tanks can also be useful for managing stormwater onsite. This is most common used in combination with soak holes. This systems gives the ground enough time to soak excess water which prevents any surface or ground related flooding.

How big does my detention tank need to be?
In Auckland, a rule is based on several conditions such as the “storm of the 100 years” principle, which would be to allow for 100 liters per 1 square metre of roof surface area. Depending on detention requirement, the outlet orifice can range between 10mm-40mm. Some further information can be found regarding size of detention tank from Auckland Council here.

We at Rotational Plastics can help you get the detention tank you need for your home. See our large range of plastic detention tanks or call us on 0800 768 284 today!

If you are looking for a Drainlayer to install any of our tanks, please don’t hesitate to call Drainage NZ for a free quote.