ENDURO Water Tank 5,000 Ltr

Those corrugated grooves are not just for show. They’re integral to the performance of the small Promax ENDURO water tank, the strongest of its type in New Zealand.   

The corrugated side walls add unrivalled strength and durability to this above-ground water tank; it’s strong enough to be partially buried and will provide years of maintenance-free water storage. A small ENDURO is a perfect option if you require a compact tank for harvesting rainwater for your garden, bach, or pool or to top up your mains supply and reduce your water bills. It’s the premium model in our small tank range with many benefits. 

  • Corrugated side walls for extra strength 
  • Maintenance-free, one-piece moulded construction 
  • Easy installation with multiple inlet/outlet opportunities 
  • Clean, fresh, untainted storage for drinking water and household use 
  • Range of seven colours to suit your surroundings. 
  • Certification to AS/NZ 4766 - Polyethylene storage tank standard 


Please note: We recently completed an update of our product codes and descriptions. New codes are effective from 1 June 2022. For reference only, the old code for this product is: PMXST05000

$2,384.00 (incl. GST)

Code Description Capacity(L) Diameter(mm) Height(mm) Weight(kg) Manhole Dia(mm) Outlets(mm)
EN1005000 ENDURO Water Tank 5,000 Ltr 5000 1600 2690 100 450 1x32

A Promax detention tank and a Promax retention tank are not the same. Sure, they look the same, and indeed, they are both stormwater tanks. But the way they are set up makes them very different. This guide will explain that difference and show you why the words “detention” and retention” are not interchangeable.

The stronger your water tank, the more peace of mind it will give you. It will be better able to withstand the elements at their most extreme and act as a reliable water source for many years. At the same time, you want a water tank that is relatively easy to install. You'll be pleased to know Promax plastic water tanks are incredibly robust and durable but light enough to make the installation process straightforward.

Potential customers often ask us, “What size water storage tank do I need?” At first glance, it might look like one question with a range of complex answers. However, at Promax, we prefer to explain things in simple terms, so we will sum it up in one response: buy the biggest tank possible. In our experience, no one has ever complained that their water tank is too big.

Extra capacity means more water, and we know our customers always find a way to use it. A prime example is in our increasingly drought-stricken regions, where people can access the rainwater they’ve collected in their storage tanks and keep their lawns and gardens alive through frequent watering. There is no such thing as too much water in dry areas, and therefore, no such thing as too much tank volume. Read more here.

When discussing the respective merits of plastic water storage tanks and their concrete counterparts, there are no prizes for guessing where our loyalties lie. Promax is New Zealand's premier manufacturer of superior polyethylene water storage and transport products. Our plastic water tanks combine several significant advantages that make them the smartest choice for residential or rural settings. Read more here. 

No, you cannot use your tank in place of a retaining wall. Uneven pressure on your tank  has the potential to deform and damage the tank.

However, you can recess your tank into a bank, provided there is a clear space between the two.

Yes, this is possible with the 25 and 50mm corrugated tank fittings. Extra charges may apply. Find out more about Promax Corrugated Tank Fittings here.

The key difference between our ENDURO and XPRESS Water Tanks is the ENDURO range has corrugated sides while the XPRESS range has smooth sides. Other key features of each include but are not limited to:

  • The corrugated profile of the ENDURO range adds a lot of strength to the sidewall of the tank.
  • The ENDURO 10000, 25000 and 30000L tanks can be buried up to 1m into the ground, can be backfilled against if needed.
  • The ENDURO Tank comes with 2x  50mm outlets while the Xpress tanks comes with 1x 50mm outlet.
  • ENDURO Tanks are available in 7 colour options while the XPRESS range is available in 2 colour options. Click here for our colour chart.
  • Both the XPRESS and ENDURO range have the same warranty.

Each project will have varying requirements so if you are unsure what you require, please get in touch with our friendly team.

Click here for video demonstration of the strength between these tanks.

No, there is no plastic tainting or taste whatsoever.

All our tanks are manufactured from virgin plastic certified to AS/NZS 4020: 2002 Potable (Drinking) Water Standard & AS/NZS 2070: Part 1 and Part 8 Australian Standards for Food Contact.

With a full tank of water there is no noticeable temperature increase. However, in summer with only a small amount of water in your tank you can expect a minor increase in temperature.

To bed your tank you should use either:

  • Sand
  • Scoria
  • Gap 20 metal

Yes, you can bury our small Promax corrugated tanks (up to 5000L) up to a third of their total height.

There are 4 inlet/overflow panels located on the dome of your roof specifically designed for installing inlets/overflows on your big tank. These will take up to 100mm PVC pipe.

Yes, you can use the Promax balancing kit  to join tanks together.

This kit contains all the fittings required to install a 50mm water balance pipeline between two tanks, including an isolating ball valve.

You can shop our products right here on our website. Alternatively, our products are available to be purchased nationwide through most leading rural and plumbing merchants.

Our stockists include: 

Some hold a standard range in stock, others will order on request.

The Promax Tank Fitting kit contains all you need for fitting your Promax or Xpress Tank to your pump and water source.

Fitting kit contains:

  • 2 x Promax Pipe seals - 90mm
  • 1 x Reducing nipple 50mm - 25mm
  • 1 x Promax Plastic Ball Valve - 25mm
  • 2 x Promax Hose Couplings - 25mm
  • 1 x 2m Flexi suction delivery hose 25mm
  • 1 x Roll Thread Tape

We recommend you use a professional tank cleaning company to do this. A professional tank cleaning company is able to vacuum the base of your tank without emptying the water. Happy Tanks can clean your Tank if you are in the Auckland and Northland regions. We recommend a Google search to find a local cleaning company for your area. 

If you would like to clean the tank yourself, please see the links below for instructions on how best to do this.

Alternatively, you could consider installing a Tank Vac. These will remove build-up of sediment already present and help keep your tank clean all the time.

We offer a variety of colour selections. Browse our range of options to find one that will best compliment your surroundings. Click here to view our  Tank colour selections.

We recommend using a registered plumber or drainlayer to install your water tanks. Visit our recommended installers page to find one in your area. If you wish to install yourself, we recommend you follow the guidelines provided in the following resources:

At Promax, we pride ourselves on making things easy for you. This includes helping you understand how council consents work. Our team is familiar with the processes surrounding consents, and wherever possible, we'll assist you based on our knowledge of these requirements. Read more here.


We offer a range of speedy shipping options, including North and South Island delivery trucks constantly on the road to ensure your tank gets to you as quickly as possible, and in top condition. Whatever it takes to maximise your storage and minimise your wait.

Click here to see our current lead times 

The short answer is that polyethylene tanks are safe in every department. If you have any doubts about the safety of polyethylene water storage tanks, this article should dispel them.

...Read More

Yes, a Wallace Seal can be used to seal the pipe to the tank. It is important to note that a Wallace Seal, not a Uniseal, should be used as it has a deeper throat to seal inside the corrugation and is more malleable. We recommend installing the seal no more than 500mm down the side wall of the tank.