500 litre Plastic Water Tank

Mist Green
Heritage Green
Light Grey
Dark Grey
Slate Grey

Big Water Tanks manufactures and sells high quality, potable water, Plastic Water Tanks. Our range includes some of the heaviest tanks on the market and we pride ourselves on manufacturing and supplying superior products. This 500-litre water tank is a great looking, extremely tough and robust plastic tank.

*Please note: We have a few of these in stock at the moment, call us to check what colours are available today


500-litre Plastic Water Tank

      • A heavy-duty tank with a strong, conical roof design that has hinged-lid access.
      • This18kg small tank is strongly built and is tough enough to withstand the test of time.
      • The tank is available in a range of colours and is designed for potable drinking water.
      • Outlet size: 25mm BSP
      • Tie down eyelets on this tank makes it easy to install and secure in-place.
      • Fully formulated long term UV stabilisation rated at UV20 providing superior UV protection.
      • Hinged manhole access with removable lid
        • Please contact us should you wish to use this 500-litre water tank for any other use.

    Tank Standards 

    • Raw Material
      • Type: Medium Density Polyethylene
      • Standard: AS/NZS 2070 - Food Contact Requirements
    • AS/NZS 4020:2005 - Potable Drinking Water
  • Diameter 0.775m (775mm)
    Height 1.275m (1275mm)
    Weight 18 kg
    Volume 500 litres
    Outlet 25mm BSP
    UV Rating UV20
    Compliance Australian food contact requirements (AS2070:1,8) and potable (drinking) water standard AS4020
  • Feel free to contact us should you have any questions or need any further information.


    We have a full range of Accessories to add to your water tank(s) including:  

    • Why Choose Big Water Tanks?

      Big Water Tanks 300l - 10,000l plastic water tanks are heavy duty and built to last. If you compare them to other products you'll see the difference in weight and thickness, this makes them renowned for their strength and quality. Some tanks are supplied with tie down eyelets to make them easy to install and secure once in place.

      Tank Top

      Proven ridging design on the top prevents the possibility of sagging.

      Plastic Material

      Our Plastic is manufactured here in New Zealand to an incredibly high NZ AUS Standard and is suitable for potable water

      Our plastic resin has been specifically designed as a large tank grade material with the best UV Stabilization available

      The plastic resin complies with Australian food contact requirements (AS2070:1,8) and potable drinking) water standard AS4020

      No Corrugations

      Our tanks have no corrugations or indentations, the reason for this is strength.

      We Believe that the corrugations create a weaker tank because they allow for more movement like an accordion in a vertical direction creating small stresses at each corrugation

      In the process of rotational moulding corrugations are thinner on the convex curves and thicker on the concave creating an uneven wall thickness through the tank,

      The larger surface area of a corrugated tank means that with the same amount of plastic the effective wall thickness is reduced

      How does Delivery work?


      Please use the checkout procedure for estimates on freight, we reserve the right to cancel an order if freight is incorrectly calculated by our website, our site cannot calculate some rural areas or island deliveries, we will contact you if there is an issue with a freight costing to your location.

      We Deliver Water Tanks throughout the North of North Island, Our rates are based on distance, that makes us a bit more expensive for "far away" deliveries we can arrange freight to most islands, please call us or contact us with your address and details we can confirm the price for the delivery

      Delivery Process

      Our Delivery prices are subject to our approval and are to the "gate", however we will normally assist putting the tank into its final location if it is safe for us to do so and our vehicles can make the trip, sometimes a digger or crane is required in hard to reach locations

      How do we Install a Water tank?

      Buried Tanks

      A buried tank needs careful consideration and every situation is a little different, while our tanks are strong enough to be buried up to 500 mm we recommend that you give us a call to discuss your specific situation (Note: Tanks Smaller than 1,000l may NOT be buried).

      Tanks like swimming pools can pop up out of the ground if there is no water in them, if a tap in the house is left on in the middle of winter when the ground is very damp, if the tank empties the buoyancy is huge it will lift out the ground and will break connection pipes and mean the tank would need to be reinstalled...

      As a simple guide you cannot bury a tank deeper than the lowest part of your section or natural drainage with a 1:100 fall. So if you have a flat site or section with no falls or that is very flat, burying the tank is not recommended or covered by our warranty in the event of uplift.

      Download our Instructions

      Download a PDF of our installation instructions

      How Much Water Storage is needed?

      Lets keep this simp"ish" because there are a large number of factors that increase or decrease water usage....

      An average house is 200m² with an average rainfall of 1200mm thats 240,000 L rainfall a year

      If you collect all your water (none overflows) that the following per person per year:

      • 1 Person 657L
      • 2 Persons 328L
      • 3 Persons 219L
      • 4 Persons 164L
      • 5 Persons 131L

      The New Zealand water usage average is about 200L per person per day (this is an average not conservative country living...)

      In Summer months the average north island water fall is as low as 72mm / month, this can be as low as 10-20mm per month in bad months...

      Our small Water tank range can store up to 10,000L of water this with a minimum rainfall of 30mm for 3 months on a 150m² roof is:

      5,000L if full + 30 x 3 x 150 = 18,500L for 90 days of bad weather

          • 1 person 205L
          • 2 Persons 102L
          • 3 Persons 68L
          • 4 Persons 51L
          • 5 Persons 41L

      10,000L if full + 30 x 3 x 150 = 23,500L for 90 days of bad weather

          • 1 person 260L
          • 2 Persons 130L
          • 3 Persons 87L
          • 4 Persons 65L
          • 5 Persons 52L

      As a basic rule 1 10,000L tank for up to 1 person and 2 10,000L tanks for 2 people

      Give us a call, drop us an email or message us on the below links we can assist you with your calculations based on your area and roof.