Slimline Water Tanks

Promax Slimline water tanks from 1,000L to 5,000L. The flat profile fits along a wall, fence, or narrow site where a standard round tank will not fit. Available as standalone tanks or as a tank and pump combo. Stormwater compliant. 7 colours. Built-in seismic bracing system certified to IL2. Promax can supply PS1 documentation (available at additional cost, contact us for details). 5-year pro-rata warranty. Made in New Zealand.

For round tanks, see Small Water Tanks (up to 5,000L) or Large Water Tanks (10,000L and above)

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30,000L Industrial Tank - XPRESS in Dark Grey, Image 1

5,000L Slimline Water Tank

$4,848.00

3,000L Slimline Water Tank

$3,878.00

2,000L Slimline Water Tank

$2,958.00

1,000L Slimline Water Tank

$2,146.00

5,000L Slimline Water Tank & Pump

$5,915.00

3,000L Slimline Water Tank & Pump

$5,278.00

2,000L Slimline Water Tank & Pump

$4,308.00

Slimline Seismic Bracing Set

P.O.A

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Why You Need a Slimline Water Tank

Not every site has room for a round tank. On urban sections in Auckland, Wellington, and Christchurch, the gap between the house and the fence is often less than 600 mm. A standard round tank will not fit. A slimline tank solves this problem: it sits flat along the wall and takes up minimal usable space.

In Auckland, the median new section size has shrunk by a third over the past three decades and now sits below 500 m2. Houses on new developments stand wall to wall. Builders and drainlayers choose Promax Slimline because these tanks fit in the narrow space between house and fence and come with built-in seismic bracing, reducing installation costs.

Councils increasingly require stormwater management for new developments and renovations. Promax Slimline tanks are stormwater compliant, simplifying the building consent process.

Rainwater harvesting from the roof lowers the water bill and provides an independent supply for irrigation, laundry, and toilets. Even a 1,000L tank noticeably reduces mains water consumption.

When a slimline tank is the right choice:

Narrow site or limited space between house and fence
Council requires stormwater management for building consent
You need a rainwater tank pump combo for supply into the house
Appearance matters: slimline tanks come in 7 colours to match your home
You need a compact water tank for an urban section

What a Slimline Water Tank Gives You

A slimline water tank sits along the wall and does not take space from the yard. On a typical urban section this is critical: every square metre counts. The flat profile lets you place a tank where a round one will not fit.

The tank and pump combo comes with a factory-fitted pump, ready to go. Minimal on-site work: connect to the downpipe and to the points of use. The pump provides pressure for supply into the house (laundry, toilet, irrigation).

All Slimline tanks have a built-in seismic bracing system certified to IL2 (residential, commercial, industrial buildings). No posts required: bolts to a concrete pad. Promax can supply PS1 documentation (available at additional cost, contact us for details) for NZBC compliance.

What Capacity to Choose

Range: 1,000L to 5,000L. The right size depends on roof area, number of occupants, and intended use. Contact Promax for help selecting the right volume.

1,000L: the most compact and lowest tank in the range. Suits sites with height-to-boundary restrictions. For a small garden or as an addition to an existing system.
2,000L: a balance of volume and compactness. For irrigation and laundry. Available standalone or as a tank and pump combo.
3,000L slimline tank: a popular balance of volume and footprint. For irrigation, laundry, and toilet. Available standalone or as a tank and pump combo.
5,000L slimline tank: the maximum volume in the Slimline range. For a larger household or full domestic use. Complete rainwater harvesting cycle from a large roof.

Tank and pump combos are available for 2,000L, 3,000L, and 5,000L. The pump is factory-fitted and ready to connect. If one tank is not enough, multiple slimline tanks can be linked using a Tank Balancing Kit.

Colours and Design

Slimline tanks are available in 7 colours: Monument Grey, Dune Grey, Kiwi, Black, Heritage Green, Lunar Grey, Beige. The 1,000L is also available in Stainless Steel.

The flat profile and vertical orientation let the tank blend visually with a fence or wall. Unlike round tanks, a slimline tank does not protrude into the yard space.

Material: polyethylene. Compliant with AS/NZS 4766 (polyethylene storage tanks). Tank and pump combos also comply with AS/NZS 4020 (contact with drinking water).

Seismic Safety

All Promax Slimline tanks come with a built-in seismic bracing system certified to IL2 (residential, commercial, industrial buildings). No posts required: bolts to a concrete pad.

Promax can supply PS1 documentation (available at additional cost, contact us for details) for NZBC compliance.

A standalone Slimline Seismic Bracing Set is available for 3,000L and 5,000L tanks as an additional accessory.

How Much Space Does a Slimline Tank Need?

Slimline tanks are designed for narrow sites. Exact dimensions depend on the volume. The tank sits flat along a wall or fence. Allow clearance for access to fittings and downpipe connection. Contact Promax for exact dimensions for your chosen volume.