8 Oct 2025
In-slab water detention solutions not only offer an effective way of detaining stormwater and mitigating the risk of flooding, they also offer the perfect solution to meet New Zealand's increasingly stringent stormwater management requirements.
We all know that with our increased rate of new housing, our aging water infrastructure is struggling to cope. It is no surprise therefore that councils are increasingly mandating hydraulic neutrality, meaning of course that a new development's stormwater discharge must not exceed pre-development levels.
In-slab solutions (or pods as they are sometimes called), temporarily store the water and then gradually release it into the public stormwater system. By integrating this water storage into the building's foundation or under areas like decks and lawns, they provide a durable, discreet, and cost-effective solution for a wide range of residential projects.
Engineering the best solution
With the increasing demand for these products, new players are entering the market all the time. Engineers, along with property owners, developers, and building professionals, need assurance that any products used are not only structurally sound but well tested.
As a partner to Engineering New Zealand, we want to assure you that we take the engineering requirements around our in-slab solution, called Aquacomb, very seriously. In fact, Aquacomb was designed by a structural engineering company to work seamlessly with waffle raft foundations and provide compatibility with all other foundation types. The product can also withstand two tonnes of distributed load and even earthquakes.
Aquacomb in slab. Image: Watersmart
Test and test again
All in-slab products are tested at manufacture. Whilst rare, there is however the chance that damage, such as steel penetrating a tank, may occur onsite. To mitigate the impact of any such damage we perform an additional pressure test prior to the concrete being poured.
Whilst a qualified plumber can install an in-slab solution, we ensure that our installers go through formal training and a proper certification process. Due to our experience of over 7,000 installs, we know that this helps to ensure the proper testing is done plus a trouble-free outcome for all involved.
Free design service for engineers
We also aim to make things easy by offering engineers a free design service. We don’t just ship the tanks to site but aim to add value to every project we are involved in. We particularly thrive on solving tricky challenges – so if you have a challenging design issue send it our way!
Get in touch
www.watersmart.co.nz
0800 110 808
This article was supplied by Watersmart, one of our partners. While we are pleased to share insights from our partners, Engineering New Zealand does not verify all claims and does not endorse specific products or services.
