All About Plastic Water Tanks

A plastic water tank is the most cost-effective, easy-to-move and reliable water storage solution for potable water.

Why you should choose a Plastic Water Tank

Plastic water tanks are extremely durable and are manufactured from a high-quality base resin, which includes high levels of UV stabilisers. The tanks are available in a range of beautiful colours, chosen to complement your home's style and design.

Plastic water tanks are made using high-grade Polyethylene plastic.

Our Grade of Polyethylene Plastic

We manufacture our high-quality plastic water tanks from a Hexene co-polymer-based Linear Low-Density Polyethylene (LLDPE), which is specifically designed for rotational moulding.

Our supplier is a multinational company with manufacturing plants based in New Zealand and Australia. They manufacture the base material here in New Zealand, meaning that the plastic has been designed to withstand the harsh Australasian environment.

The material meets all the requirements for ~ 

  • AS/NZS4766:2006 (Polyethylene storage tanks for water and chemicals) Standards
  • AS2070-1999 (Plastics materials for food contact use sec.4.1.1(a) 
  • U.S. FDA CFR 177.1520(c)3.1a

All the pigments used in the range of tanks are heavy-metal free.

Tank Material Properties

Physical Properties

 Test Method



MFI (2.16kg; 190°C) ASTM D1238 3.0 g/10min
Density ASTM D1505 0.939 g/cm³
ESCR1 (F50) ASTM D1693 >1000 Hours
Flexural Modulus ASTM D790 790 MPa
Tensile Strength @ Yield ASTM D638 20 MPa
Tensile Strength @ Break ASTM D638 30 MPa
Tensile Elongation ASTM D638 1000 %
UV Rating ASTM D2565 15000 Hours
UV15 UV rating

*Correct at time of publishing

Transporting Tanks

Transporting 30,000-litre water tanks is only practical if they are manufactured from plastic. Concrete water tanks of 30,000-litre would be much too over-sized to fit onto standard New Zealand roads without employing pilot vehicles and incurring massive delivery costs.

Most concrete tanks are 20,000 to 25,000 litres or smaller. Concrete tanks weigh tons and require Hiabs or cranes to move them into place, whereas plastic water tanks (even our heaviest standard NZ-made 30,000-litre plastic water tank) are only 500kg.

Watch the video - Unloading a tank from the side of a delivery trailer

Tank Sizes

Plastic water tanks are available in a wide range of sizes from 10 to 50,000 litres and encompass many different uses and applications.

We specialise in manufacturing 30,000-litre water tanks as anything larger is no longer cost-effective - a little more storage capacity with a much larger price tag.  The 30,000-litre tank is the largest, "easy-to-transport" tank on the market.

Tank Pricing

Specialising in only one size of tank has made us price competitive and kept our overheads lower than our competition, which means that you can purchase a well-priced water tank. Furthermore, we do not have any distributors to take care of so we can pass better prices on to you, the home owner.

Pricing Comparison for 2019

Our competitors' prices range from $3,695- to $4,309- for a 30,000-litre plastic water tank and from $3,050- to $3,569- for a 25000-litre water tank.

Have a look at our Products pages and you will see that we offer our tanks between $3,195- and $3,295- plus freight. We are very competitive in the following regions:

  • Auckland
  • Waikato
  • Northland
  • Northern Bay of Plenty

While we do make deliveries to outlying regions, our prices are more inline with our competitors' pricing including freight:

  • Taranaki
  • Gisborne
  • Hawkes Bay
  • Manawatu Whanganui
  • Wellington

Currently, we do not deliver to the South Island but are looking to do so in the future.

Corrugated, Ribbed or Straight-walled Tanks

There are a few differences between the options available for the side wall of your new water tank.

At present, there are 5 manufacturers of large water tanks in New Zealand:

  • One manufactures "ribbed" tanks
  • One manufactures "corrugated" tanks (and recently added straight-walled tanks to their portfolio, too)
  • Four manufacture "straight-walled" tanks


Our design belief is that a straight-walled tank has the most even spread of stresses and the tank can expand "naturally" under the force of 30 tons (30,000l) of water. This is the similar belief of the majority of tank manufacturers in New Zealand.


We feel that the ribbed tank is the weakest version because the stresses are increased by the rib not being able to move as much as the flat wall. The flat wall is able to expand while the rib is held tighter by its shape. This means that the ribbed wall could fracture.


Our view on corrugated tanks is that the difference in stresses are not that big between the corrugations and that the corrugations do offer some strength.

However, during the rotational moulding process, plastic thickness is only controlled by gravity and the thickness of a concave edge (convex on the inside) is thinner than the thickness of a convex edge (concave on the inside) meaning that some areas will be stronger than others. There is also a lot more surface area for the plastic to cover, meaning the tank would necessarily weigh more than our competitors' tanks.

However, these tanks are the lightest tanks on the New Zealand Market, with the smallest plastic thickness.