Completely hidden solution, saves space, time and water too!


Are you building a new home? Perhaps you’re landscaping? Planning a new driveway, or building a deck or garage?

Let us introduce you to Aquacomb® On-site Detention (OSD)

Save time, space and money too! 

Aquacomb is New Zealand’s first in-slab stormwater system and it is simple and quick to install too! Our system saves days in construction time and significantly reduces building costs.

The system can be designed into any type of slab construction and is especially suited to waffle pod slabs used in housing. Aquacomb® can be located in the slab, deck, lawn, patio and/or driveway. They can go behind retaining walls, under stairs or even stacked on their edge under soffits.

Unlike traditional solutions, the entire Aquacomb® system is hidden from view meaning no overground pipes and no big, ugly water tanks taking up valuable space on your property. Better still, they are significantly cheaper than underground tanks.

Aquacomb® OSD is an established fully modular system, which has completed over 10,000 trouble-free residential construction installations over the past 14.

Why Choose Aquacomb®


Save Time

Quick and easy to install. Most systems can be installed in a few hours.

Save Money

Simple modular system means no large engineering or excavation costs and reduced trades. Up to 38% cheaper than traditional underground tanks.

Save Space

Invisible water storage. Aquacomb is completely hidden from sight, so you save valuable land space.

Dual Purpose

Can be used for both water retention (reuse) and detention, or potable water storage.

Solves Challenges

Laid at grade – solves high invert levels or rocky grounds. Perfect for difficult sites that could otherwise not be developed.

Strong and Durable

Aquacomb® pods do not leak and can withstand earthquakes. Almost maintenance free when installed with silt traps and leaf slides.

Rainwater can be collected for reuse outside. It can also be used to wash clothes and flush toilets. This represents 56% of water use for the average household.


A figure that is on par with the average water bill savings from Hobsonville Residents who collect rainwater for the same purpose via using a WaterSmart solution.


It is possible to use rainwater entirely, although this may require additional filtration for hygienic purposes (drinking, showering, dishwashing etc.). If you plan to connect a tank to your internal plumbing, you will require a building consent.


Get in touch with your local council for specific information related to your area.

This depends on the size of your roof. The following estimate is based on an average roof area of 200 sqm in each of the main regions –

  • Auckland – an average of 17,000L per month
  • Hamilton – an average of 18,000L per month
  • Wellington – an average of 20,000L per month
  • Christchurch – an average of 9500L per month

Use our rainwater collection calculator for an estimate of what you could collect.

This depends on what you use your rainwater for. If it’s outdoor use, you could save on average 18%. But of course, you could save considerably more if you have a pool, boat or water gardens and lawns frequently.


If you have rainwater plumbed back into your house to wash clothes and flush toilets, this amount can jump to 56%.


You can use rainwater for everything, although this may require additional filtration for hygienic purposes (drinking, showering, dishwashing and so on).


If you plan to connect a tank to your internal plumbing you will require a building consent. Get in touch with your local council for specific information related to your area.

Combined Use System - Detention & Reuse

If you are building a new home, it’s likely you’ll be required to install a water detention system. Aquacomb® can be used for combined detention and water reuse.

Depending on if you have a larger detention requirement or large retention need, you can customise how many Aquacomb® pods you allocate for each purpose. Find out more about water detention, what it means, how it works and how it differs from water reuse.

Aquacomb® uses high quality recycled Polyethylene to construct our stormwater tanks. PE will stay strong and not degrade after years of continual use. The connecting pipes (Polypropylene) and seals (EPDM) along with the water pumps are also 100% safe for storing and reusing rainwater.

Aquacomb® water tanks are made from a recycled plastic mix, helping to reduce the environmental impact of your home.

Your One Stop Water Saving Solution

WaterSmart provides you with an end-to-end solution for saving water and money.


Each property is unique, and so our team will design a rainwater collection plan based on your needs.



What’s the best solution for you? Our team of helpful experts will talk you through your options, so you can make the right WaterSmart choice for you.


Whatever solution we recommend, our team of qualified installers work efficiently and to the highest standards so you don’t have to worry about a thing.


Our technicians carry out checks to ensure your solution stays in peak condition, for optimal water management.

Each council has specific requirements that must be met in relation to rainwater collection and storm water runoff.
Our team can help you understand what these are so your solution is not only perfect for your property and needs, but compliant too.


Each property is unique, and so our team will design a plan based on:

  1. Whether your project is a new build or a renovation
  2. The size of your roof
  3. Location on site – deck, lawn, driveway, patio, slab (we’ll consult with you to work out best option!)
  4. How much rainwater you want to collect
  5. Your budget
  6. What you want to use the water for: e.g. gardening, vehicle washing or in the home use


All installations are completed by approved installers who have been trained by the WaterSmart team to install Aquacomb®.

They are qualified plumbers or drainlayers. This ensures that all our quality control measures are met and compliance with the council’s stormwater regulations.

Typically installs only take a few hours and no longer than a day for large projects. We also take care of producer statements required by councils for sign off on projects.

Please click on the play button over the image to watch our quick installation video for more information.

Play Video


WaterSmart’s solutions are designed to prevent leaves and debris from entering your tank, so very little maintenance is required. However you can opt for a servicing plan that includes one of our technicians:

  • Checking leaf guards and filtration devices are working correctly
  • For re-use systems: checking the pump controller and black flow valve is operating to standard
  • Checking to see whether the homeowner has any questions!

Aquacomb® FAQ's

Encased in concrete: In a slab foundation, under a driveway or carpark. The pods can be stacked up to three high under decks or under houses on piles, or under your garden/lawn. The only limitation is your imagination!

Aquacomb® can be only be installed by our highly skilled WaterSmart team, this is part of our strict quality control process.

Short answer – They won’t! In over 15,000 installs over 15 years in Australia and New Zealand there has not been a single leak, so we are very confident that if the system is installed by our WaterSmart team there will be no problems.

Each Aquacomb® is 1100mm x 1100mm and either 225mm (250L) or 300mm (350L) deep. When joined with connecting pipework we allow 1.44m2 for each Aquacomb® pod.

We divert all (or majority) of downpipes from the roof to a centralised location at the AquaPit, which acts as a gateway in and out of the Aquacomb® system.

For a detention system, gravity does the trick! The outlet is at a lower level than the inlet. For re-use system, a pump is connected to extract the water from the Aquacomb® system - same as any other tank.

Our overflow prevention system is extremely simple but effective. If the system ever fills up past 100% the water will simply be diverted to the council stormwater connection through an overflow pipe in the AquaPit.

The key to a long-lasting system is debris and sediment prevention from the start. Every downpipe feeding water into the system should have a WaterSmart leaf diverter to divert leaves away from the tank, and our specially designed AquaPit stops sediment entering the system.

The AquaPit should be inspected once a year and cleaned out as needed by hand, or with a wet vac.

The extremely minimal amounts of sediment that do get into the tank are very fine, and normally wash away with the water.

It is recommended that the Aquacomb© system should be inspected annually, and vacuumed out when needed, usually not more than once every ten years. This can be done by any tank cleaning company. For Auckland based installations we recommend Hydrovac who has assessed the system for its cleaning needs.

As the Aquacomb© tanks have been designed so that the lowest pipe is 20mm off the bottom of the pod, any sediment that does manage to settle, will always stay in the first pod of your system, meaning only the first pod will ever need to be cleaned out.

An official letter outlining cleaning recommendations from Hydrovac can be had on request.

To learn more about maintenance, view our Homeowners Manual. 

Independent testing by Design Navigator (the online tool used by architects to model thermal performance of buildings for Building Consent) determined that the effects on insulation properties was less than the margin of error in the calculator, therefore deemed to be the same as polystyrene void formers in a slab.


Even so if using in-slab heating systems we do tend to stay away from living areas when designing systems, opting for areas such as garage floors.

Ready To Collect Your Own Water Supply?

Get started by requesting a free consultation!