*Aquacomb tanks installed in slab foundation for stormwater detention.*

In-slab stormwater detention protects Woodridge views

Cottonwood Lane, Woodridge

This new family home sits on a prime site in Woodridge, with wide views across the valley towards Churton Park. The property required 7,250 litres of stormwater detention, but finding the right place for a conventional tank presented a challenge.

Installing the detention system within the foundation provided a practical alternative. Using 29 Aquacomb pods, the full volume could be accommodated beneath the home without taking up outdoor space or affecting the view.

Project overview

Location: Cottonwood Lane, Woodridge, Wellington

Project: New family home exceeding 200 m²

Stormwater function: Detention only

Required detention: 7,250 litres

Solution: 29 × 250-litre Aquacomb pods

Architect: Andrew Sexton Architecture

Builder: Woodridge Homes

Installer: DM Plumbing & Gas Ltd

Installation: November 2025

The challenge

An above-ground stormwater tank would have been highly visible from the home and taken up usable space around the property.

Placing a tank underground was another option, but it would have added significantly to the cost and construction programme. The work would have involved further excavation and soil disposal, along with a 200 mm reinforced concrete slab over the tank. It would also have created more disruption on a site that Woodridge Homes keeps particularly clean and tidy.

Wellington’s wind was another consideration. As the property is in a high-wind zone, the team wanted to avoid using polystyrene void formers that could break loose and be carried beyond the site.

The solution

Aquacomb made it possible to build the required detention into the home’s concrete slab.

The 29 pods provide a combined capacity of 7,250 litres. They temporarily hold stormwater before releasing it at a controlled rate, helping to manage peak flows into the downstream network.

The Aquacomb system was installed alongside Firth X-Pod void formers. Together, they provided a zero-polystyrene foundation that was well suited to the exposed site. Both systems fitted neatly into the foundation layout, addressing the home’s void-forming and stormwater requirements within the same area.

Installation

Watersmart trained DM Plumbing & Gas Ltd to install the Aquacomb system ahead of the work in November 2025. The installation went smoothly, with the pods laid out and connected as part of the wider foundation works.

Including Aquacomb in the foundation programme meant there was no need for separate tank excavation or the additional structural work an underground tank would have required.

The result

The finished Aquacomb system provides the full 7,250 litres of stormwater detention beneath the home. No outdoor space was lost, and the outlook across the valley remains unobstructed.

It also gave the project team a cleaner and more efficient alternative to an underground tank, while supporting the zero-polystyrene approach chosen for the foundation.

For a site where the view was one of its greatest features, keeping the stormwater system out of sight made sense.