Promax

Together, making a difference today to sustain life tomorrow.

In 1992, we made our first tank in a kiwifruit packing shed in Whangarei. We were never going to stay there. As a brand and a business name, Promax means maximum performance and delivering complete customer satisfaction. You can't achieve those things in a packing shed. From day one, we wanted to make the best tanks in New Zealand - not for the sake of our ego but because it would help us stay true to the words that drive us: Together, making a difference today to sustain life tomorrow.

"To sustain life tomorrow" is at the heart of the Promax story. In the late 1980s, Tim Strachan ran a kiwifruit orchard and engineering business in Northland. Like hundreds of thousands of New Zealanders, Tim was also dealing with the fallout from the 1987 stock market crash. The market plunged by nearly 15% on Tuesday, October 20, and in the months following "Black Tuesday", the value of New Zealand's market shares was halved. For Tim Strachan, who had to provide for his six children, it was time to branch out and ensure a better tomorrow for his family. In doing so, he started our company, one that now sustains life all around New Zealand.

Tim's new enterprise provided what many in the Auckland region desperately needed; water storage for rural and residential customers. With his farming background in the arid region of Northland, Tim knew how important it was to capture and use every drop of rain. A prolonged drought in the early 1990s meant the city began to run out of water. By May of 1994, the collective level of Auckland's water supply reservoirs was just over 30 %. At about the same time, Tim and his son Hamish began making water storage tanks in a Whangarei packing shed repurposed into a temporary factory. The first product they rolled out the door was a 3000-litre above-ground water tank, and demand for Promax tanks was constant and instant. As Hamish says: "We made them in the morning and sold them in the afternoon."

On retiring in 2016, Tim handed over the company's management to his sons Walter and Hamish. Managing Director Walter Strachan has over 15 years of experience in the Rotational Moulding business. His brother Hamish Strachan, our North Island Factory Manager, has been involved with Promax since its inception and is still a driving force in our direction and innovation.

In 2007 Promax opened an impressive site in Rangiora in the South Island, and in 2010 we commissioned a state-of-the-art facility in Kerikeri in the Far North. Today's manufacturing facilities are far removed from our humble beginnings in that kiwifruit packing shed. Instead, they're world-leading plants boasting in-house resin compounding and massive kilns that produce thousands of tanks every year, including the ultra-strong corrugated tanks for which we're renowned.

Promax works closely with the Rural, Build, Civil and Industrial markets. We combine innovative design and manufacturing excellence to bring a comprehensive range of products to each sector. Our team constantly develops new solutions that keep pace with an ever-changing marketplace. The corrugated tank is just one example of Promax innovation. We were never afraid to take a different approach when bringing new products to the market in the early years. We were all about moulding pretty much anything out of plastic back then. Today, while innovation is still our point of difference, we have refined our product range in line with what our customers require. As a result, we now focus on where it all started in 1992: liquid storage.

Our team includes qualified engineers who use specialist software to create exceptional products, experienced sales representatives who work closely with their clients to provide customised solutions, and an exceptional customer service team who tirelessly support our customers. With North Island and South Island sites and a fleet of delivery trucks, we can provide superior products and customer service nationwide. As we grow as a company, so does our desire to be a sustainable organisation, and we continue to reduce our environmental footprint.

To find out more about the right Promax solution for your next project, visit our product section or give our friendly team a call.

At Promax, quality is everything.

"We deliver more than tanks. We deliver solutions."

Our products solve problems. Whether they capture the rain that falls on drought-prone regions or create reticulated water systems on farms affected by new stock exclusion regulations, Promax provides water tanks, liquid storage, and transport solutions to four sectors: Rural, Civil, Industrial, and Build. We combine exceptional design with manufacturing excellence to bring you a comprehensive range of products that look good and work even better.

The quality of our products confirms what our clients have been saying since 1992: Promax is New Zealand's premier manufacturer of superior polyethylene water storage and transport products. Our premium range includes corrugated water storage tanks designed for optimum performance over many years. Promax is the only New Zealand company to make corrugated tanks, highlighting our most significant point of difference: innovation.

Our square-shaped, ENDURO underground water tank is yet another example of our inventive thinking. The tank's shape reduces excavation and backfill requirements, while the unique solid-filled rib design can withstand all the ground pressures applied to the tank over its long lifetime. It's part of one of the most versatile and highest-quality ranges of underground tanks in New Zealand. Our underground stormwater and wastewater tanks are designed for the effective retention or detention of stormwater or secure and reliable storage of potable water.

Many of our products are customised to meet the requirements of specific projects, and you can learn more about some of them here. But we can also provide standard "off the shelf" answers. A prime example is our range of XPRESS water tanks, made from high-grade polyethylene plastic so you can have Promax quality at an affordable price.

As well as water tanks in all sizes, shapes, and applications, we are proud to bring you the best colostrum tanks in New Zealand. They're robust, secure, and manufactured from translucent food-grade polyethylene, making it easy to monitor how much colostrum you have remaining in the tank. We set similarly high standards with our septic tanks, where there's no room for compromise. Hygiene and safety are paramount, and the tank's structural integrity must be flawless. Perfection is what you get in every Promax septic tank.

All Promax tanks are certified to AS/NZ 4766, and our detention tanks are fully tested and designed to withstand ground and water pressure, even at depth. The Promax Underground Tank is engineered by geotechnical experts and Finite Element Analysis tested (FEA). Our Enduro tanks are so strong they are the only plastic water tanks in New Zealand that can be buried up to one metre and still retain a 20-year warranty! Promax is also authorised to use the BSI registered Benchmark Product Certification Trademark on products identified in the Product Certification Schedule. You can view this here.

To help you get the most out of your tank, we also have all the accessories you'll require. They include pumps and covers, tank level indicators, fittings, fire coupling kits, leaf eaters and everything else you need to keep your rainwater storage safe, secure and clean.

Visit our product sections to learn more about the entire range of Promax products.

Whatever you need, whatever the issue, you'll soon discover that we deliver more than tanks. We also deliver solutions.

Promax makes things easy. That includes helping you and your customers choose the right product for the job.

It’s as simple as requesting your copy of the Promax Specifiers Pack. This pack provides you and your clients with the correct technical information to comply with an ever-growing list of regulations. It’s a power-packed tool which provides you with all the resources you need when specifying for clients or presenting plans to councils. The pack is a quick and easy way to review our products and the standards they meet, and will help to ensure you choose the best liquid storage solution for your customer’s project. The pack includes:

• Operation and maintenance guides
• Modification plans
• Drawings and dimensions
• Product brochures and catalogues
• Case studies
• Fitting installation guides
• Typical Schematics

We believe that choosing the right product for the job shouldn’t be difficult. Obtaining that vital information is just as easy.

Request the Promax Specifiers Pack here

Promax calculator tools are grouped below by application, including rainwater, underground tank design, stormwater compliance, and wastewater planning. Start with the section that best fits your project, then choose the calculator that matches the decision you need to make.

Rainwater Tank Size Calculator

The Rainwater Tank Size Calculator helps estimate an appropriate storage volume based on roof catchment area, rainfall zone, and expected water demand. It is a practical starting point for households looking to improve water security, reduce reliance on mains supply, or plan a rainwater system with greater confidence before moving into product selection.

Slimline Specification Tool

The Slimline Specification Tool helps identify the right slimline tank setup for sites where space, access, and layout all play an important role. It is designed to guide users through the selection of tank size, fittings, and pump configuration so the final solution is better matched to the realities of the site and the intended use of the system.

Underground Specification Tool

The Underground Specification Tool helps match Promax underground tanks to site conditions such as cover depth, traffic loading, riser requirements, and installation setup. It is intended to support builders, contractors, and installers who need a clearer understanding of what configuration is suitable for the project and what practical factors need to be considered before installation begins.

Enduro Partial Volume Calculator

The Enduro Partial Volume Calculator helps determine partial fill volumes and critical invert levels for Promax Enduro underground tanks. This is especially useful on projects involving detention, retention, or controlled outflow, where accurate volume and level calculations are important for design confidence, system performance, and more effective project planning.

SMAF Calculator

The SMAF Calculator is designed to support stormwater planning by simplifying Auckland SMAF detention and retention calculations. It helps users assess stormwater outcomes more efficiently and provides a clearer starting point for projects where compliance, attenuation, and site performance all need to be considered together.

Detention PRE-POST Calculator

The Stormwater Detention PRE-POST Calculator helps compare pre- and post-development runoff to support detention planning and broader stormwater assessment. It is a useful tool for projects where development changes site hydrology and where a clearer understanding of runoff impact is needed to inform design decisions, consent pathways, and detention requirements.

Septic Tank & Soakage Field Sizing Tool

The Septic Tank & Soakage Field Sizing Tool helps estimate suitable septic tank and soakage field requirements based on site-specific conditions and wastewater design needs. It gives homeowners, plumbers, and specifiers a more informed starting point for planning on-site wastewater systems, making it easier to understand likely system requirements before progressing to detailed design or approval.

Contact our team

Need help with product selection? If your project needs more guidance, the Promax team can help you work through tank selection, site considerations, and the next steps from early sizing through to a suitable solution. This is a useful option for projects that fall outside a straightforward calculator pathway or where extra support is needed to confirm the right approach.