Custom & Industrial Tanks
Promax designs and manufactures engineered polyethylene tanks for industrial, civil, and infrastructure projects across New Zealand. From early-stage design support through to certified delivery, every tank is built to perform exactly as specified.
Why Choose Promax?
Across New Zealand, Promax helps industrial operators, system integrators and engineers deliver safer, more compliant liquid storage systems, backed by engineering rigour and proven production.
Engineered Solutions
Reduced Install Friction
Cost-Effective
Early-Stage Design Support
Ventia Caustic Soda Storage.
INDUSTRY: WATER TREATMENT
PRODUCTS: CAUSTIC SODA TANKS
LOCATION: KERIKERI
Challenge:
Ventia required additional caustic soda storage for the Kerikeri Water Treatment Plant within a confined footprint, while meeting hazardous substance containment and seismic requirements.
Solution:
Promax designed a fully bunded HDPE storage system sized precisely to the footprint, providing design, access port configuration and all documentation. The tanks were engineered for HSNO compliance, bunded containment and safe site delivery.
Outcome: The engineered design was approved on first submission and delivered on schedule, giving Ventia a compliant, low-maintenance solution that removed corrosion risk and simplified operations.
“ We engaged Promax to design and manufacture a caustic storage solution tailored to our site requirements. Their technical support, communication, and delivery performance were excellent, and the finished tank system has been reliable and fit for purpose. ” - TODD RIDDELL, VENTIA
Built for the sectors that can’t afford uncertainty.
Every project follows a defined, traceable process. This gives engineers, project managers, and system integrators confidence that the vessel supplied will perform exactly as intended.
Consultation
We start by understanding the project, what liquid is being stored, the available space, seismic category, and installation constraints. Early collaboration removes guesswork and lets Promax take the ownership expected from a proactive supplier partner.
Design
The design team develops a tank configuration and installation plan. Certified engineers review and sign off plans, supplying PS1 documentation and material suitability reports for submission and approval.
Manufacture
Every tank is rotationally moulded in New Zealand using UV-stabilised, high-density polyethylene. Fittings, access ports, and seismic anchor points are all taken care of before the tank leaves site.
Documentation
Each project is backed by comprehensive documentation including CAD drawings, technical data sheets, compliance certificates, and installation guidance, so the paper trail is watertight for everyone involved.
Delivery
With manufacturing sites in Northland and Rangiora, delivery can remain fast and freight costs kept in check for industrial and infrastructure projects across New Zealand.
Rolleston College
INDUSTRY: EDUCATION
PRODUCTS: CUSTOM ENGINEERED HYDRAULIC TANK
LOCATION: ROLLESTON
Challenge:
The Rolleston College expansion required a hydraulic water tank capable of meeting the site’s high seismic demand of Cd(t) = 1.17. Standard rotomoulded tanks were not suitable at this level, and Southbase needed certainty that the hydraulic supply would comply without triggering late-stage redesigns.
A misstep here could have caused programme delays — a delay which would cost thousands in liquidated damages if opening was delayed due to a simple non-compliant tank.
Solution:
Promax worked with Southbase and Aurecon to deliver a 30,000 litre custom designed and built hydraulic tank, fully engineered for the site’s seismic conditions.
The final package included: the tank, seismic restraint and anchoring interface, slab design, compliant venting, access manhole, pipe configurations, and all required penetrations.
By resolving the engineering up front and supplying a fully documented, fit-for-purpose system, Promax removed risk from the programme and ensured the hydraulic installation progressed without disruption, keeping the project on track.
“We needed a tank that would meet the seismic specs with no pushback — it had to comply. We foresaw the problems and delays that come with a non-compliant tank, and engaged Promax early. It’s refreshing to talk to people who understand this, and Promax designed and delivered what we needed to keep the job moving, compliant, with no delays”
Built For Sectors That Can’t Afford Uncertainty.
Promax delivers on projects that move, treat, and store liquids — from critical process facilities to municipal infrastructure. Our tanks are engineered for safety, compliance, and installability, enabling designers and contractors to integrate watertight storage systems without compromising quality or schedule.
Food & Beverage Manufacturing
From dairy to confectionery plants, our hygienic and insulated HDPE tanks handle ingredients, wash-water and waste streams safely. They offer engineered compliance and lighter, corrosion-free performance compared with stainless steel.
Agriculture & Dairy Processing
Promax designs robust tanks for wash-down systems, effluent management and chemical handling. Each vessel is built for harsh rural conditions and meets seismic and compliance demands of modern processing sites.
Chemical Manufacturing & Distribution
Purpose-built for hazardous liquids, our bunded and dangerous goods tanks are designed for HSNO compliance. Clear documentation and PS1 support make sign-off straightforward for integrators and auditors.
Wastewater & Water Treatment
Trusted by system integrators and councils nationwide, our vessels are used for the storage and dosing of treatment chemicals, pH correction and backwash processes. Each tank is configured for input/output fittings, and seismic restraint to ensure long-term reliability and operator safety.
Fire Sprinkler Storage
For high importance-level buildings where mains-independent fire systems are critical, Promax is the trusted name in water storage and smart solutions. Whether the available space is narrow or the storage volume is large, Promax has your fire water storage under control.
Energy & Resources
Across refineries, power stations, and renewable sites, our HDPE tanks manage process fluids, fire water, and chemical storage. Durable, UV-stabilised, and easy to maintain, built for performance in demanding environments.
Need Help Choosing the Right Solution?
Send us a few details and our team will point you in the right direction.
Whether you need help choosing the right product, understanding your options, or finding the best solution for your project, we are here to help.
If you would like to speak with our team, call us on 0800 77 66 29.
Easy to specify
Easy access to technical specs, drawing files and compliance documentation.
Easy to install
We engineer ease and practicality in for the every link in the value chain.
Built for purpose
Every vessel is tailored to your requirements - from access ports and fittings to seismic restraints.