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Infratank - tanks

Commercial Large Underground Tanks

INFRATANK™ make HDPE tanks from 4m³ to 1000m³+ in NZ for potable, storm, waste or chemicals. Below/above ground, fast and flexible design up to 3.2m diameter.


Infrapipe Infratank Download Information for Professionals large HDPE Tanks

Offering the best in water storage, INFRATANK™ offer exceptional design with the best in manufacturing from our experienced fabrication team using 100% virgin polyethylene material.

INFRATANK™ are manufactured from INFRAPIPE™ New Zealand’s, latest pipe manufacturing machine from Europe to provide a solid, strong and reliable tank body providing the very best in structural integrity.

INFRATANK™ solutions are customised to meet the requirements of specific projects and our design engineer can assist optimising the design to meet any customer specifications, requirements and location for all applications.


Once the primary chamber is made in a diameter from 1000-32000mm, end plates with bracing are added, risers, sumps, inlets, outlets, overflow, ladder rungs, washdown systems and pump stations.

Infratank tank

Underground water and storage tanks offer secure and reliable storage. Each INFRAPIPE™ underground tank is designed by experts to ensure it can withstand the demands of subterranean environments.

Infratank Tank

HDPE is ideal for waste and sewer applications as it is chemically inert, has no boundary layer and can be modified using extrusion welding quickly, easily and without creating any weaknesses or inconsistencies for the waste to attack.

Volume Table

Tanks can be joined to create even greater volumes or make the best use of constrained spaces. Typical dimensions and tank volumes are mentioned in the table below.

Tanks can be made in different configurations to those below, and larger ones simply require onsite joining by INFRAPIPE of sections to create a tank as large as necessary.













































Other diameters available: 1100,1200,1350,1600,1800.

Product Attributes & Benefits

INFRATANK™ large underground tanks combines strength, performance, quality, longevity and exceptional durability.


Durable Underground Tanks: Sizes, Flexibility & Eco-Friendly Options

  • Scalable Solutions: Choose from underground tanks ranging from 1 meter to 22 meters long to perfectly fit various project needs. Large capacity, underground tanks are the perfect choice for maximizing space on small sites.
  • Diameter Options: Our tanks come in a variety of diameters, from 600mm to 3200mm, offering versatility for any application and flexibility for diverse storage requirements. Additionally, multiple tanks can be linked to create even larger capacities for your growing needs.
  • Lightweight Design: Easy transportation and installation thanks to our lightweight tank construction, reducing labor costs.
  • Ultimate Flexibility and Versatile Design: Customize your underground tank with inlets, outlets, overflows, pumps, accesses, sumps, risers, and connectors for tailored configurations. The tank can be made in most shapes to optimise site usage.
  • Simple Installation: Save time and effort with our easy on-site connection system.
  • Durable Performance: Engineered for a 100-year design life, ensuring long-lasting reliability.
  • Sustainable Choice: Reduce your environmental impact with our fully recyclable tanks.
Infratank tanks

Large Underground Tanks: Applications

INFRATANK™ provides the ideal storage or treatment solution for a wide range of liquids across various sectors, including farming, industrial and chemical. Typical applications for storage and process tanks are:

  • Chemical storage and process tanks.
  • Process tanks.
  • Scrubber.
  • CO2 Stripper.
  • Tanks for water treatment.
  • Silos for agriculture.
  • Silos for food industry.
  • Biogas plants/composting plants.
  • Fodder storage.
  • Storage tanks for the textile industry.
  • Drinking water tanks/reservoirs.
  • Overflow tanks.

INFRAPIPE™ underground water tanks are a trustworthy solution for various applications. Install them confidently under driveways, footpaths, car parks, and more.

Get Answers to Your Underground Tank Questions!

Our FAQ covers everything you need to know about underground tanks, from types and sizes to installation and maintenance.

Can INFRAPIPE™ tanks incorporate washdown systems?

Absolutely, HDPE easily accommodates internal systems.

Are they trafficable?

Yes! INFRAPIPE™ tanks can be designed to take any load with as little as minimum 600mm of cover.

What are the requirements for installation?

Typical bedding material is GAP 20/40.

How easy is access to the inside of an INFRAPIPE™ tank?

INFRAPIPE™ tanks can be designed with as many manholes and ladders as required.

Is flotation an issue for INFRAPIPE™ tanks?

For sites with a high ground water table, fittings can be supplied to avoid the risk of flotation.

Do we need a professional design service?

No. INFRAPIPE™ need the soil details and will then design it for you.

What types of connections are available with these tanks?

Our tanks provide connection options such as flanged, threaded or butt-welded based on factors like tank material thickness, flow rate, and stored liquid type.

Can we modify this tank?

Yes, the beauty of HDPE is at a later date you can modify, create or remove connections.

Contact us

INFRAPIPE™ offers a comprehensive range of New Zealand’s most versatile and high-quality underground water and storage tanks for effective stormwater retention or detention.

Please contact us if you would like to discuss any of our products or services.

Pressure Test For Leaks

The Reliable Way to Find Leaks

Every tank completed by our experienced fabrication team is air-tested for leaks.

The tank has to hold pressure for 15-20 minutes at 0.5 bar. Should the pressure gauge show a pressure drop, a soapy solution is sprayed on all welded joints looking for any bubbles foaming on the weld being checked. If this occurs the tank has to be depressurized and the weld is redone.

The tank is then rechecked under pressure before sign off by the tank fabricator as leak-free and ready for dispatch to the customer.

Infratank Tank Pressure Test for leaks
Our HDPE underground water tanks undergo rigorous testing to guarantee they can handle ground and water pressure at depth.

Tank Inlet/Outlets Additions

Complete Tank Solutions

The tank’s design can have multiple fittings added due to the requirements needed for water entering and leaving the tank.

Optional fittings may include inlets and outlets, providing the connection utilising electric fusion couplers, bends, T-junctions, and puddle flanges with backing rings to have a variety of different valves added.

Infratank Tanks
Infratank Tanks
Infratank Tanks

INFRAPIPE™ underground tanks long-lasting performance and reliable storage for your needs.

Any fitting can be added in any location and orientation giving the user greater flexibility with site design.


Delivering on quality is what we do!

Infrapipe Tank

INFRATANK™ can be delivered completed in the North Island but delivered South Island depending on size may have to be shipped in sections and welded on site.

See to the left a 2.5m diameter by 19m 86m³ capacity stormwater emergency storage tank, delivered complete to Tamahere Country Club in Hamilton, North Island.

Our largest tanks can be 3.2m in diameter giving 96m³ for each 12m section (which can be joined endlessly to give storage in the hundreds or thousands of m³)

**NOTE Oversized tanks may require the use of a pilot vehicle.

Design Assistance

We Engineer Optimal Tank Solutions

Infratank Tanks

Customized tanks require technical specifications and accurate calculations, for different applications.

CAD drawings can be supplied on request or can be altered if required for redesign due to a change in requirements such as ground water level, load ratings, soil conditions.

Wastewater and stormwater tanks can also be installed with internal spray wash down systems for high- or low-pressure options.

INFRATANK™ design goes beyond functionality. Our tanks are built to last, minimizing their environmental footprint. By partnering with INFRAPIPE™, you can be confident you’re getting a high-performing, environmentally responsible tank for your liquid storage or treatment needs.



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Our goal is to provide cost-effective products that are manufactured from recyclable materials. The manufacturing process limits waste which limits carbon impact.

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