Order now and spring rain does the filling, so your tank is full before summer starts. NIWA is forecasting a strong El Nino summer, which usually means drier conditions across much of the country. We can help you get prepared.
Our strongest, most versatile tank.
ENDURO is our strongest tank: corrugated walls, buriable up to 1m, seven colours. XPRESS is smooth-walled and gives you the most litres per dollar. Same UV-stabilised plastic, blended in-house, same heavy ribbed roof, same 20-year warranty, and both delivered free to your gate. Sale prices run until 30 September. After something smaller? Every size from 450L is further down the page.
More sizes
Sale pricing applies to ENDURO and XPRESS water tanks 10,000L and over and ends 30 September 2026. The 20-year warranty applies to standard large water tanks; tanks under 10,000L carry 5 years. Industrial, seismic and engineered tanks carry their own warranty terms. Free delivery applies to mainland New Zealand. Online pricing is available to anyone ordering through the website and cannot be applied to merchant accounts. Every tank is made to order, so lead times are shown on each product page and at checkout.
Both are genuine Promax tanks built to the same standards. The ENDURO is the premium tank. The XPRESS gives you the most litres per dollar.
Our strongest, most versatile tank. The corrugated sidewall is the Promax signature - and the reason it can do things other tanks cannot.
Genuine Promax quality at a sharper price. A real Promax tank with the extras trimmed to hit a price.
Both built without compromise:
Real installs from our case studies - from single-tank tiny homes to 28-tank community supplies.
28 ENDURO tanks supplying the township were shaken by the magnitude 7.8 earthquake at forces of around 3g - no failures. Locals now call them 'the tanks that withstood the earthquakes'.
Their 3,000L ENDURO has never frozen - even at minus 9 degrees - and an autumn fill from a 30 square metre roof carried their tiny home right through a Queenstown winter.
Six corrugated 30,000L tanks, partially buried to keep pipework frost-free, hold the firefighting reserve and buffer supply for the whole retirement village.
ENDURO is our strongest tank and the safe pick for most homes and farms. XPRESS gives you the same Promax quality with the most litres per dollar on the big sizes. Slimline tucks in against a wall where space is tight. Pick a range to compare every size, side by side.
450 - 30,000 L
Corrugated walls for extraordinary strength, up to seven colours, and the widest spread of sizes - from garden top-up to full rural supply.
Large tanks
Small tanks
2,500 - 30,000 L
Smooth-wall construction and the most litres per dollar in the range. Mist Green or Dark Grey.
Large tanks
Small tanks
1,000 - 5,000 L
Flat-backed tanks that sit tight against a wall or fence - serious storage where space is the constraint. Tank-and-pump combos available.
Tank only
Tank and pump
Tank-and-pump combos are listed alongside the tank-only options.
Rain harvesting
Leaf diverters, filters and fittings that keep the water in your tank clean. Add them to your tank order and everything arrives together.
Start with what the water is for. Garden and stock top-up: under 5,000L. Household rain supply: 25,000L or more is the usual starting point. Rural supply and fire reserve: 25,000L to 30,000L, often several tanks linked together. A useful rule of thumb for rain harvesting: every 1mm of rain on 1 square metre of roof collects 1 litre of water, so a 150 square metre roof in 1,000mm-a-year rainfall can harvest around 150,000 litres annually. Not sure? Send us your details below and we will recommend a size within one business day.
Order now. A tank ordered in spring fills off your roof through the wetter months, so it is already full when you need it. A tank that arrives in January arrives empty. NIWA is forecasting peak El Nino conditions over the 2026-27 summer, with the upper North Island carrying the country's strongest dry signal this spring. Sale pricing on ENDURO and XPRESS water tanks 10,000L and over ends 30 September.
ENDURO is our strongest tank: corrugated walls, up to seven colours, sizes from 450L to 30,000L, and the only range that can be partially buried. XPRESS delivers the same Promax quality with smooth walls and the most litres per dollar, in two colours from 2,500L to 30,000L. Slimline tanks are flat-backed for tight spaces - 1,000L to 5,000L, with optional pump packages. If you are unsure, the ENDURO is the safe pick for most homes and farms.
Yes. Promax tanks are made from premium UV-stabilised polyethylene that we blend in-house, compliant with AS/NZS 4766 and suitable for storing potable water. Poly will not rust, crack or leach like some older tank materials, and the sealed one-piece construction keeps light and contaminants out of your stored water.
Decades. Our UV-stabilised polyethylene is engineered for New Zealand's harsh sun, and the one-piece construction means there are no joins or seams to fail. Standard water tanks 10,000L and above carry a 20-year warranty; tanks under 10,000L carry 5 years. Industrial, seismic and engineered tanks are a separate range with their own warranty terms. For real-world proof, the 28 ENDURO tanks at Waiau went through the magnitude 7.8 earthquake without a single failure.
Only the ENDURO. Its corrugated sidewall is strong enough that large ENDURO tanks (10,000L+) can be inset up to 1m and keep their full 20-year warranty - useful for downpipe fall, sloping sites, frost-protecting your pipework, or keeping the tank out of sight. Smaller ENDURO tanks can be buried up to a third of their height. XPRESS and Slimline tanks are above-ground only.
Poly tanks need a flat, level, well-compacted base that fully supports the tank floor and is slightly larger than the tank's footprint - compacted basecourse topped with sand or crusher dust is the common approach. Keep the pad clear of roots, rocks and sharp objects. Full site preparation guidelines are on each product page, and our team can talk you through your specific site.
Tanks are made to order at our North Island and South Island factories and delivered free across mainland New Zealand, including rural addresses. Lead times are shown on each product page and again at checkout, so you know the timing before you pay. Delivery is arranged after you order and depends on your location - the team confirms the details with you directly.
Yes. The price shown on each tank is what you pay at checkout. Each tank is made to order, so current lead times are shown on the product page and at checkout.
Ordering direct through the website keeps the admin out and the price sharp. Anyone can order online and pay by credit card, debit card or bank transfer. Online pricing cannot be applied to merchant accounts.
Still got questions? Ask the team →
Ordering more than one tank, or working out water storage for a larger project? Tell us what you're trying to achieve, where it's going and how much you need to store, and we'll come back with a clear recommendation. No jargon, no obligation.
