Stormwater Detention Tanks and Available Options

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Stormwater Detention Tanks and Available Options
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If you are building a new home, then there might be a number of requirements your local council expects you to meet. Depending on where you are located, one requirement might be effective stormwater planning and installation of stormwater detention tank.

Local authorities will often stipulate how much water needs to detained and acceptable drainage rate into the storm water system. So, what are stormwater detention tanks? What options are available? This article will explore these questions.

What are Stormwater Detention Tanks?

In heavy downpours, normal rainwater tanks can quickly fill up. If this happens, excess rainwater will overflow into your stormwater drainage.

What makes stormwater detention tanks a “detention tank” rather than a “rainwater tank” is that detention tanks are intended to remain empty. This is especially important when consecutive downpours occur, with rain stopping and starting over several days.

So, unlike a typical rainwater tank, the distinguishing feature of a detention tank really amounts to a fitting – detention tanks are specially fitted with a valve to slowly release water over time into your stormwater drain.

Stormwater Detention Tank Configurations

In a stormwater detention system that makes use of storage tanks, there are two tank setups:

  1. Detention tank setup – this is where one tank is configured to slowly release any water it receives over time, or
  2. Retention tank setup – a specially made dual use tank that can both retain rainwater, and detain water to be released over time.

Team Poly’s round tanks, slimline tanks, and Li-Lo underground tanks allow for both these configurations – a pure stormwater detention setup, or a special purpose tank system that can both retain and detain a set amount of water.

With the dual-use configuration, rainwater is harvested into the bottom half of the storage capacity. When full, the outflow is activated and the detention capacity becomes available for the slow-draining water detention storage.


If you need to comply with stormwater detention requirement on your property, talk to our expert team today. Rest assured we can provide a solution to meet your needs.