Custom Size Water Tanks

Steel Water Tanks From 500 to 37,000 Litres
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Custom Water Tanks

Custom water tanks is what we do and we have thousands different sizes available for all requirements. Different sites have different rainwater harvesting challenges.  Sloping blocks might require a series of water tanks at different heights so they will balance properly.  A low set house on a large property might require squat tanks with a large diameter and low inlet height.  Whatever the challenges Select Water Tanks will help find you the perfect solution.

Jumbo Stainless Slimline

This customer needed custom water tank to hold 20,000 litres on a long skinny block in Paddington.

Under The Deck

Custom sized under deck tanks are perfect for sloping sites.

Commercial Water Tanks

Custom water tanks for industry with commercial fittings.

Space Saving

Custom Aquaplate / Colorbond Slimline Water Tanks are perfect for wash bays in high traffic areas.

Slimline Water Tanks

Slimlines are perfect custom sized tanks for narrow blocks or yards without a lot of space.  They can fit down the side of a garage or shed without stealing too much real estate.

Select Water Tanks can manufacture down to a minimum width of 550mm for very tight spaces.  It’s important to consider the height of a very slim water tank.  As a general rule, the tank should not be more than 3 times as high as its width.


  • Length Increments:  100mm
  • Width Increments:  50mm
  • Height Increments:  76mm (approx)
  • Common Heights:    1255mm, 1560mm, 1860mm, 2350mm.

Custom Water Tanks – Slimlines In Various Sizes

Need Help with Pricing?

For a full list and breakdown on pricing for all Our Steel Water Tanks, Filtration Systems & Accessories.
Please click below or contact us.

Round Water Tanks

If you have the space, a round water tank is by far the best value for money. Round water tanks do not require additional reinforcing, as Slimlines do, so they cost less to manufacture.  They are also easy to clean and maintain.

Select Water Tanks can manufacture a round water tank up to almost 37,000 litres.  Measuring 3900mm in diameter x 3100mm high, this tank requires a crane to position.  Alternatively, we can manufacture a tank that you could fit in the back seat of your car.


  • Diameter Increments: 100mm
  • Height Increments:  76mm (approx)
  • Common Heights:  1255mm, 1560mm,1860mm, 2350mm, 2800mm, 3100mm

Round Custom Water Tanks – In Various Sizes

How Do I Know What Size Water Tank I Need?

Download Our Rainwater Harvest Yield Graphs and Information based on the assumptions below.

It can be difficult to know just how much water storage capacity you might need for a whole-of-house rainwater harvesting system.  There are several factors to take into consideration:

  • Number of occupants in the household
  • Average rainfall in the area
  • Size of catchment (roof area)
  • Available space on site
  • Budget

Let’s start with a few assumptions:

  • 45,000 litres of total capacity is a good starting point for a whole-of-house rainwater harvesting system
  • A catchment size of 250 square metres
  • The average daily water usage per person is between 150 and 200 litres. Some geographical areas report higher usage.  At the higher end of the scale, a family of four would use approximately 24,000 litres per month.
  • Monthly average rainfall figures for a certain area are widely available on the internet. For this exercise we are researching monthly rainfall in Currumbin Valley, Qld.  These figures are available at

The relationship between the catchment size and rainfall is key to determining the desired capacity of your system;

10mm of rain on 100m2 of catchment will result in 1,000 litres of harvested rainwater

Other factors including evaporation, absorption, first flush diverters, or gutters full of debris are not accounted for in this example.


What Our Customers Say

More Than Just a Manufacturer of Steel Rainwater Tanks

Select Water Tanks make steel water tanks that are longer lasting, better looking, healthier, and can be custom made in terms of shape and size. They can be made from either grade 304, marine grade 316 stainless steel or aquaplate steel.

Knowledge & Experience

25 years manufacturing experience.

Quality Guaranteed

Highest quality Stainless steel water tanks backed by 30 years non corrosion warranty. Our Aquaplate Tanks are backed by 20-years non corrosion warranty.

Industry Leading

We are the first Australian company to design and manufacture stainless steel water tanks.

Tailored Solutions

We find the perfect solution for your rainwater harvesting system needs.

Looking for Help or Advice?

If you need any help with Steel Water Tank Pricing, Custom Sizing, Delivery Charges or anything else
Please contact us today - we are here to help.