Practical, plain-language guidance on choosing, installing and maintaining water storage, written by the Promax team.
Concrete and asphalt stop water soaking into the ground, which drives runoff, cuts groundwater recharge and carries pollutants into waterways. Dual purpose tanks tackle it by doing detention and retention in one tank, which also satisfies SMAF controls.
Read the guideEmpty underground tanks are buoyant, and on flood-prone or high groundwater sites they will float. Uplift restraints strap the tank to concrete-filled boxes to hold it down, and you need roughly one set for every 1,000 litres.
Read the guideCouncil stormwater rules differ from region to region, so the tank you need depends on which rule applies to your site. Promax detention tanks and sizing calculators take the guesswork out of the number.
Read the guideRigid concrete tanks cracked in the Christchurch and Kaikoura earthquakes, and Promax replaced many of them. We have had no recorded failures of our plastic tanks after those events, which is the clearest answer we can give on material choice.
Read the guideRoof to tank, tank to pump, pump to changeover device: how a rainwater reuse system is plumbed, the backflow prevention it needs, and what a council wants documented.
Read the guideA detention tank and a retention tank look identical and are both stormwater tanks. A detention tank slowly releases water to the stormwater network; a retention tank holds it for you to use.
Read the guideTP108 sets out how stormwater mitigation is calculated and managed. What the guideline covers, and how Promax calculators based on it size detention and retention tanks.
Read the guideA dual-purpose tank detains stormwater in its top section and retains water for reuse in the bottom, so the same tank that satisfies the council also feeds the laundry, the toilets and the outside taps.
Read the guideSMAF, or Stormwater Management Area Flow, is a component of the Auckland Unitary Plan that splits stormwater management into SMAF 1 and SMAF 2 areas. This is an orientation to what the framework covers.
Read the guideBrowse Promax tank categories for residential, rural, commercial, and specialised applications.
Durable above-ground water tanks for rural, residential, and commercial storage.
Underground water storage for sites where space, access, or visibility matters.
Narrow-profile tanks designed for homes, boundaries, and other restricted spaces.
Specialised tanks for demanding commercial, industrial, and process applications.
