Next level underground tank technology is here.
When your retention or detention tank has to fit underground, either very deep, in a shallow space, and/or for vehicles to drive over, APD’s StormLite3® has your ideal solution. Its unique modular rectangle system is extremely durable and watertight, using the same reliable 6mm polyethylene sheet that is used on our hazardous-rated chemical tanks. Installation has never been this easy, arriving on-site complete and ready-to-go. All you have to do is specify your requirements, then fill-in over the top of the highly durable delivered tank.
When you need underground stormwater detention or retention but are constrained by:
Our newest Tank Solution StormLite3® does it all with its unique APD design.
Designed to support loads up to 28 tonnes/sqm.
Solutions strong enough to support up to 2m of ground cover and/or withstand heavy traffic loads, so long as the overall 28 tonnes/sqm load limit is not exceeded.
As New Zealand’s leading plastic tank fabricators we know what it takes to make a robust tank shell.
We’ve combined our expertise and high quality materials to produce a 6mm thick shell that securely holds the modular tank elements together and is over 7x the thickness of the protective layer used by other modular systems. Every weld on every tank is leak tested during production.
So it can be installed quickly and safely, our StormLite3® tank is delivered complete with spigots for an inlet and vent pipe ready to connect to a manhole.
Tanks are supplied with lifting lugs, to simplify handling on site.
Fast installation saves costly additional man hours on site, keeping the time spent in the excavation site to a minimum; making for a safer and efficient work environment.
Minimum Tank Height: 458mm (1 Module)
Maximum Tank Height: 2150mm (5 Modules)
Maximum Buried Depth: 3m from base of tank
Maximum Cover Over Top of Tank: 2m
Maximum Tank Width: Approx. 4500mm (Requires Special Transport)
Maximum Tank Length is dependent on the height and width. Please contact APD for advice.
Minimum Cover to Finished Ground Level:
Non-Trafficable Install: 300mm
Driveway/Trafficable Install: 600mm
The StormLite3® tank must be connected to a manhole chamber as per the diagram, to limit silt intake into the tank and as a connection point for all inlets, overflow and orifice/outlet.
Modular tanks that fit any environment and give you the flexibility you need.
The internal structure of StormLite3® is composed of ProTank modules, arranged to utilise space effectively, fitting your volume requirements and site layout.
ProTank modules have a void space ratio of 0.95 and lock together vertically, up to 5 high, and pack together horizontally to form the shape of the tank.
Standard with all StormLite3® tanks are a tank connection spigot and a vent spigot for connection of the tank to a manhole chamber as shown in the illustration above.
Add on options are:
APD StormLite® Detention and Retention tanks can be installed under house or decks where space permits. Key requirements for this type of installation are for the tanks to not undermine any of the structural support of the building or for the tanks to be placed anywhere that a surcharge load can be applied to them by the building structure.
If the tanks are not to be completely buried then the minimum burial depth for the tanks is half the height of the cylindrical tank diameter. The tank shown in these images is a 1000mm diameter tank and it has been buried to a height of 500mm from the tank invert.
The Taupiri Development Project required that Storm water Detention Tanks be installed to detain storm water draining from the carpark area, prior to controlled discharge to the local stream. The Detention Tank design agreed on, was to have two underground Detention Tanks joined together to create a combined volume of 16.5 cubic metres (16,500 Litres) of storm water detention.
The StormLite® Storm water Detention Tanks were manufactured by APD as a matched pair, with built in 250mm outer diameter spigots to allow easy connection of the tanks during installation by Comins Plumbing & Gas Ltd. The Storm water Detention Tanks were each 10.8metres long and easily handled on site during installation, by a small digger.
To cope with the potential storm water flow, a 250mm outer diameter inlet spigot was added. Holes were pre-cut for overflow and outlet pipes and a pre-drilled orifice cap was supplied to minimise installation time on site. Contact APD during the design phase of your next project to discuss your requirements.
The Sunnynook Park Development project required the establishment of new toilet blocks adjacent to the carpark in Sunnynook Road, with rainwater being collected and then reused for flushing toilets in the new toilet block.
A 6150 Litre APD StormLite® storm water tank was selected and installed by Wiltek Maintenance Ltd to retain the storm water until required.
To meet site requirements, the Storm Water tank was manufactured by APD from polyethylene to the following dimensions: 1 metre diameter by 5.6 metres long. Weight: 350 kg.
The StormLite® Detention Tank was easily handled on site during installation by the A.J. Tutill & Sons Ltd HIAB truck. The tank was lowered into position using a single strop. Try doing that with a concrete tank of similar size. See our article concrete vs. plastic for more information.
Contact APD during the design phase of your next project to discuss your requirements.
There was no easy to use off-the-shelf tank that could meet the requirements for this site. QDC Works Limited needed to be able to detain 3,000L of storm water as part of their project but because of site restrictions they needed a tank less than 500mm high, buried 1.6m underground.
APD were approached to provide a cylindrical style StormLite© tank for this project but because of the depth of cover required and tight constraints on the tank height, this wouldn’t work.
We needed to deliver a tank inherently strong enough to withstand the load resulting from 1.6m depth of cover that was less than 500mm high. Like our other tanks it had to be optimised to contain the volume required while keeping the tank as small as possible; minimising the cost.
StormLite® with its modular design that can be easily scaled up or down to suit a residential or commercial site. Rectangular in shape to optimise water capacity in the space available the StormLite3 with its unique design can withstand the pressures of increased soil cover and/or heavy traffic loads. The tank was fabricated and available within 15 days.
What makes StormLite® stand out is that, unlike any other modular tank solution on the market, it is delivered to site pre-assembled and ready to go straight into the ground.
Modular systems are typically built on site and wrapped in layers of geofabrics and a membrane. APD Stormlite3 tanks have a 25 year design life and are pre-assembled undercover in our production facility regardless of the weather conditions to:
Everything was fabricated and delivered for QDC on time and on budget providing a solution with:
Meaning QDC received a practical, cost effective solution that they know they can rely on to drain storm water safely for years to come.
Make the affordable choice, with made to order economy.
Call APD now on (09) 263 7741.
StormLite® cylindrical tanks are made to order and delivery is normally within 3 – 5 days.
APD can supply PS1 documentation and project specific producer statements on request.
At around 250 kilograms, a 5000 litre StormLite® water tank is a mere fraction of the weight of concrete tanks. This means it can be moved around site with only a small digger. Designed strong, StormLite® can go under driveways, carparks, and grass. Tell us your volume requirement, and our make-to-order service will ensure your StormLite® tank adheres to Council regulations, while making your drainlayer’s job a breeze. Make the affordable choice, with made to order economy.
Our design keeps the tank outlet level with the tank invert, and tank overflow level with the crown, giving you maximum volume of the tank is used while still meeting council regulations.
The installation is very easy, tanks are supplied complete ready to install. A Silt Trap replaces the separate chamber that might otherwise be required and where storm water retention is called for, it doubles as a pump sump. See our Rain Harvesting Systems.
Volume is customised for your site – 1m3 to 30m3 (1,000 to 30,000 Litres) and each tank is made to order to the volume specified by council.
You don’t pay for, or install more tank than you require.
Available in 4 diameters – 645mm, 800mm, 1000mm and 1200mm.
Lengths are calculated to provide specific volumes and tanks are made from tough environmentally friendly polyethylene (PE). This material never rots or corrodes and is easy to handle. All fittings are supplied – including seals, outlet end cap to drill orifice in, and leaf trap/screen.
Where space and or fall are an issue we recommend StormSlim® above ground tanks or our StormSlab® in slab tank. Above ground Rectangular tanks are also available from APD for those projects where standard detention tanks just won’t work. Great for placing under houses and decks, these tanks can be custom made to fit between piles and structural supports. Tanks can be partly buried if required.
When it comes to stormwater and hazardous substance storage, there’s not much “off the shelf” about APD. From its Wiri, Auckland factory, the 40-plus-year-old company designs and manufactures made-to-order stormwater systems and chemical storage tanks for projects across Aotearoa – often solving problems that standard products simply can’t.
From one-man band to 60-strong team
APD began life in the 1980s as a one-man plastic fabrication business, “doing just about anything made from plastic,” Chief Executive Officer, Neil Prime explains. Over time, the company moved into composite PVC/fibreglass tanks for road tankers carrying hazardous substances, then into roto-moulded tanks and fittings for water and wastewater treatment plants.
In the mid-2000s, when new hazardous substances regulations and codes of practice were introduced, APD became the first New Zealand company to have an approved code of practice for supplying hazardous substance tanks fabricated from polyethylene sheet – something they still specialise in today.
At the same time, APD expanded its offering to include below-ground stormwater tanks as the business continued to grow.
In 2018, APD outgrew its 800 m² premises and relocated to a 3,000 m² factory. Fast-forward to today, and the company has expanded again, completing yet another significant upgrade to support rising demand. We have grown to a team of around 60 people and just increased the factory to 4,000 m² with an additional 750 m² office block. We now have more space, better facilities and even more capacity for future growth.
Prime says this shift has enabled significant investment in plant and capacity including three rotational moulding machines, new bending equipment and CNC capability.
Today, APD’s business is built around three core streams:
1. Stormwater solutions – including above ground StormSlim tanks, in-slab StormSlab systems, and StormLite below-ground tanks, often integrated with pits and custom structures.
2. Water and wastewater pumping stations – including pressure sewer systems.
3. Bulk chemical storage tanks – for hazardous substances used in water and wastewater treatment, beverage and dairy processing, and industrial applications such as galvanising and powder-coating.
For Prime, what makes the company unique is a mix of technical capability, manufacturing flexibility and a deeply customer-centric mindset.
“As a plastic fabricator and a rotational moulding company, we control the process from raw material to finished product in-house. We’re not constrained to a single mould or size. We can make a solution work – and we support our customers before, during and after installation.”
What’s more, APD’s builds products that stand the test of time. Chemical tanks have a 25-year design life, while rotationally moulded stormwater products carry a 10-year warranty and an expected service life of 50 years or more.
Custom tanks as standard
APD’s underground stormwater tanks are an example of its flexible manufacturing approach. Instead of offering a fixed set of tank sizes, APD builds tanks to whatever volume a designer or drainlayer specifies.
“We can make whatever size the customer needs,” Prime says. “And there’s no custom surcharge; it’s just how we work.”
The process starts with rotational moulding. Polymer powder is poured into steel or aluminium moulds, which heat and rotate until the material melts and coats the interior. Once cooled, the parts are removed, trimmed and held in inventory. APD then cuts and welds sections together to achieve the exact tank length and capacity required.
Because the moulded parts are modular and the welding is done in-house, every underground tank is made to order – yet surprisingly, typical production time is just two to five days from order, even with no finished stock held.
“In a market where some products take months, that’s exceptionally fast,” says Prime.
Fabrication for hazardous substances
APD also fabricates chemical storage tanks for hazardous substances, using polyethylene, polypropylene or PVC sheet sourced from specialist suppliers. Sheets are cut, shaped and plastic-welded to form tanks from a few hundred litres to tens of thousands.
“It’s a bit like being a boilermaker – but with plastic,” Prime explains. “Our welding process creates a homogeneous joint, so once it’s cooled you can’t see where the material was joined.”
APD is one of only a few New Zealand companies approved to both design and fabricate polymer chemical tanks under the WorkSafe Hazardous Substances Regulations. Each tank is hydrostatically tested, welders are independently assessed annually, and designs are verified to the relevant standards.
Innovation over imitation
True to its “innovation, not imitation” philosophy, APD has brought several clever features to market in recent years.
An example is StormSlab, the company’s in-slab stormwater tank system, which won a Master Plumbers Product of the Year award. Where some competing systems use multiple small modules connected beneath the slab – each connection a potential leak point – APD moulds a large single tank and keeps all connections outside the building footprint.
“Nobody wants a leak under their slab,” Prime notes. “By having a single tank and accessible connections, you dramatically reduce risk and make any future maintenance possible.”
Another example of company innovation is the anti-buoyancy ribs moulded into APD’s pump stations and pits. Traditionally, installers pour concrete around buried tanks to prevent them floating when the water table rises. APD’s design uses shaped ribs so the backfill itself locks the tank down.
“You don’t need to pour concrete at all,” says Prime. “It’s faster, simpler, and you avoid leaving a big block of concrete in the ground.”
APD has also squared off many of its pits and tanks, because, as Prime points out, “You don’t dig a round hole with a digger. A square tank in a square hole reduces excavation size and backfill volume, saving time and cost on site.”
Quality systems and sustainability
Always striving for excellence, the company is currently working towards ISO 9001 certification. “We’re already doing a lot of it; ISO 9001 is about documenting and tightening what’s there to further support the quality of our products,” Prime explains.
On the environmental front, APD already has several practical initiatives. Polymer offcuts and scrap are segregated and sent back to suppliers for grinding and reprocessing into new sheet or powder, used in non-critical applications. Roof rainwater is captured and used for toilet flushing, hand-washing and hydro-testing tanks. Cardboard, cafeteria waste like milk bottles, and other recyclables are separated and collected to minimise landfill.
“We already have very little waste,” Prime says. “And once ISO 9001 is embedded we’ll look more formally at environmental standards as well.”
Support for installers and specifiers
For drainlayers, engineers and councils, APD’s technical support is invaluable. The company provides detailed manuals, drawings and installation instructions, plus PS1 documentation where installation follows APD’s specified details. In addition, a dedicated technical support team works with specifiers at design stage to solve layout challenges and size tanks correctly.
“We’ll often go to site before anything starts,” Prime says. “And if someone hits a problem once they start digging – wrong invert level or unexpected ground conditions – our technical people will help to work through a solution.”
Because APD is both a fabricator and a moulding house, it can modify designs with additional supports, deeper burial ratings or bespoke connections to suit unusual conditions.
“There’s not too many situations we can’t resolve,” Prime says. “That’s a big part of what sets us apart from offshore or catalogue-only suppliers.”
A culture of care
Ask Prime what he’s most proud of and he’ll point to APD’s culture. “We’ve built a team that supports each other,” he says. “Visitors often comment that there’s a really good vibe in the factory – and that’s something we work hard on.”
APD’s monthly company updates are followed by a shared lunch, with shout-outs recognising staff who go the extra mile. The company offers practical support too: factory staff can help themselves to breakfast supplies, fruit snacks and get six free doctor’s visits each year.
“We genuinely care about our people,” Prime says. “If the team is well supported, everything else flows from there.”
What lies ahead?
With strong demand in stormwater, water and wastewater, APD sees plenty of room for growth.
“We don’t have an end point in mind,” says Prime. “We’ll keep developing new products, growing the existing range and moving with the technology. For us, it’s about the company that offers the products that customers know can solve the hard problems.”
In a sector facing increasing regulatory complexity, climate pressures and infrastructure challenges, APD’s combination of custom manufacturing, technical depth and genuine customer care leaves the company exceptionally well-placed for the future.
Understanding Jointly Owned Access Lots and Underground Stormwater Design
Jointly Owned Access Lots (JOALs) are now a defining feature of modern New Zealand subdivisions. As developments become more compact and land is used more efficiently, shared driveways and accessways are increasingly common. While most people see a JOAL as simply a shared driveway, under New Zealand property law it is much more than that — and it has major implications for stormwater tank design and installation.
For developers, engineers, and planners, understanding how JOALs work is essential to ensuring that underground stormwater infrastructure is compliant, durable, and fit for purpose.
What Is a JOAL Under New Zealand Property Law?
A JOAL, or Jointly Owned Access Lot, is a legal land title used where two or more properties share a private accessway. Instead of being owned and maintained by the local council like a public road, a JOAL is co-owned by all properties that use it.
Each owner holds an undivided share in the access lot, giving them an equal legal right to use it. JOALs are governed by the Property Law Act 2007, which gives property owners rights similar to an easement, ensuring permanent legal access to their land.
JOALs are commonly used in:
They are particularly common where more than four lots need access from a single street.
Why JOALs Are Critical to Stormwater Design
Because JOALs are:
They are some of the most structurally and legally sensitive land in a subdivision.
Stormwater infrastructure located beneath or adjacent to a JOAL must cope with:
In addition, JOALs often sit at the lowest point of a site, meaning they collect runoff from roofs, driveways, and paved areas. This makes them the natural location for underground stormwater detention tanks and drainage systems.
Stormwater Tank Requirements for JOAL Developments
Most councils now require new developments to manage stormwater on site to reduce flooding and protect downstream infrastructure. This typically means installing underground stormwater tanks to store and slowly release runoff during heavy rainfall.
When stormwater tanks are installed beneath a JOAL, they must be designed to handle:
Standard lawn grade tank solutions are not suitable for this environment. A failure beneath a JOAL can disrupt access for every property on the title and create complex legal and financial issues for owners.
Why Traffic-Rated Stormwater Tanks Are Essential Under JOALs
JOALs are not landscaped areas — they are working driveways that must remain safe and functional for decades. Stormwater tank systems must be engineered for:
If a tank deforms, cracks, or settles, it can lead to:
For this reason, councils and engineers increasingly specify traffic-rated stormwater detention systems for JOAL applications.
APD Stormwater Tanks for JOAL Installations
APD designs engineered tank solutions and installation detail specifically for high-load environments such as JOALs, shared driveways, and commercial accessways.
Our systems can be engineered to suit:
Our StormLite®, StormSlab® and StormLite³ solutions are commonly used in JOAL developments because they are:
This makes them ideal for installations beneath concrete driveways, shared accessways, and high-use areas.
Protecting Property Titles and Long-Term Compliance
Because JOALs are governed by the Property Law Act, any failure in infrastructure beneath them can affect every property owner. Restricted access, flooding, or pavement collapse can create:
Installing the right stormwater system from the outset protects:
Designing Stormwater Systems That Work With JOALs
JOALs allow higher-density housing and smarter land use — but they also demand higher engineering standards. Stormwater tanks installed beneath shared accessways must be built to handle more than just water; they must support vehicles, structures, and legal access rights for decades to come.
APD’s stormwater tank systems are engineered to meet the structural, hydraulic, and legal realities of JOAL developments. (All our tanks are made to the same benchmark, whether it’s for the JOAL or standard installation in the garden or driveway, the same process in manufacturing is followed ) , ensuring compliant, durable, and low-risk outcomes for modern subdivisions.
If your project includes a JOAL, make sure your stormwater system is designed for what it really is — a critical piece of shared infrastructure beneath a shared legal title.
Baradene College Gymnasium
Client: Watts & Hughes Construction
System: StormLite® Underground Detention System
Total Capacity: 56,400 L
Project Overview
Watts & Hughes Construction partnered with APD to deliver a stormwater detention system for the new gymnasium at Baradene College.
The original design called for four joined StormLite® tanks (4 × 12,700 L) installed under a landscaped lawn area, providing a combined storage capacity of 50,800 L.
After the tanks were ordered, the project scope changed — the school decided to build a car park directly above the tank area.
This change introduced several structural and engineering challenges:
APD proposed an alternative configuration — three longer StormLite® tanks — which reduced the overall system width while maintaining structural integrity for the concrete slab above.
Two additional design adaptations were required:
Final configuration:
3 × 18,800 L StormLite® tanks (1,200 mm dia × 17 m long)
Total capacity: 56,400 L
Through careful redesign and collaboration with the engineering team, APD delivered a cost-efficient and structurally compliant solution.
The revised configuration enabled the car park construction to proceed safely above the installation — without increasing the project’s footprint or significantly impacting cost.
This project demonstrates APD’s ability to adapt designs quickly while maintaining compliance, performance, and client confidence.
“You have been exceptional to work with… extremely pragmatic, refreshing.
Simply put, for suppliers like yourself and APD — this is how you obtain repeat business.”
Understanding the role of retention tanks in smart water management.
As sustainable development becomes increasingly important, managing how water is collected, stored, and reused on-site is more than just good practice — it’s often a council requirement. One of the most effective ways to achieve this is by installing a retention tank. But when exactly is a retention tank the right solution?
Let’s explore the key scenarios where a retention tank is not just recommended – it’s essential.
A retention tank is an underground or above-ground water storage system designed to hold stormwater or rainwater for reuse. Unlike detention tanks, which slowly release water into the stormwater network, retention tanks store water permanently for non-potable uses such as irrigation, toilet flushing, or wash-down.
If your project involves rainwater harvesting for re-use in the home, garden, or commercial facility, a retention tank is ideal. It stores clean water that can be filtered and reused, reducing reliance on mains supply and lowering water bills.
Many local councils now include water reuse or retention targets in building consents for residential and commercial developments. Installing a retention tank helps meet these requirements and demonstrates commitment to sustainable water practices.
In areas where connection to public stormwater systems is limited or non-existent, retention tanks offer an on-site solution. By capturing water for later use or slow release, they help prevent surface flooding and reduce runoff.
Retention tanks are a great way to align your build with green building standards or environmental certifications. They also support climate resilience by making properties less dependent on external water sources during dry periods.
Our retention tank systems are designed for New Zealand conditions. Whether you need a standalone tank or a combined retention + detention system, we can help you size, design, and install a solution that works for your site.
APD’s retention tanks integrate seamlessly with our full range of underground systems — including StormLite®, StormSlim®, and StormSlab® — delivering a flexible, durable, and compliant solution for any project.
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