Water Tank Sizes

Pioneer Water Tanks - Water Tank Sizes from 12 000 to 500 000 Litres

Rainwater Tank Sizes

Pioneer Water Tanks have been providing the highest quality water storage to Western Australia for more than three decades, so it’s fair to say that we have experience in dealing with people’s water storage concerns, and helping them find the best rainwater tanks for their individual needs.

When it comes to purchasing a rainwater tank, the first question on most people’s minds is what water tank size they need. Whether that be due to the price of installing a new rainwater tank, the available space on the property, or how much water supply they will need annually for their home

When it comes to rainwater tanks and household water supply, everyone is different, as different lifestyles and regions lead to different water demands – but the good news is that Pioneer Water Tanks have more than 30 years of experience helping Australians meet their water storage needs, and have a wide range of water tank sizes from 12,000L to 500,000L, ensuring that your water storage needs will be met.


Pioneer Water Tanks have provided a service for Western Australia since 1988. Our high quality Australian-made water tanks will provide the long-term water security you’re looking for.

Rainwater Tank Sizes and Dimensions

What size rainwater tank do I need

What size rainwater tank is best for your home depends on a range of factors – even if you are using it as your primary water source. Factors such as annual rainfall (mm),  roof size (m²) and the number of residents in the home are the major determinate factors. 

You can calculate your annual rain harvesting ability by multiplying your roof size by your average annual rainfall, which would look something like the equation below:


Roof Size ( ) x Annual Rainfall (mm) = Rainwater Harvesting Ability

300  x 850mm = 255 000L

For the average household sizes, Pioneer Water Tanks typically recommends the following size water tanks:

  • 2 Persons: 90 000L
  • 3 Persons: 110 000L
  • 4 Persons: 150 000L
  • 6 Persons: 250 000L
However, it is important to remember these figures are simply recommendations, and should not be seen as exact. Some households have higher or lower demands than others, and some have larger roof space, and may choose to harvest additional rain in order to water gardens, lawns or animals. 

Pioneer Water Tanks also come with the option of an additional fire reserve of up to 20 000 litres, so if you are looking to use your rainwater tank for fire protection, you may want to keep in mind the extra storage when purchasing your water tank.

Bushfire e-book

Bushfire Protection with Pioneer Water Tanks

Pioneer Water Tank Sizes

pioneer water tank sizes and dimensions
pioneer water tank sizes and dimensions

The Litres/Gallons stated above are gross capacities. Actual useable volume will vary depending on the size and position of inlets and outlets.

Other sizes and measurements to consider

When installing a Pioneer Water Tank, it is recommended that the minimum size of the tank site be 2m wider than the tank diameter, leaving 1m of sand pad on each side of the tank. This means that for a GT110 – which is 8m in diameter – you would need a 10m diameter space to install the water tank.

The sand pad itself – which needs to be installed, level, stable and free of debris prior to construction – needs to be 150mm (minimum) thick of clean sand, and covered with aggregate after the tank has been installed, in order to prevent erosion and to comply with warranty conditions.

As for the location of your rainwater tank, it must be located at least 50cm below gutter height for every 100cm away from the downpipe it is situated, in order to ensure that it will fill correctly. 

Small Water Tanks

Pioneer Water Tanks specialise in large steel water tanks, but do have a range of tanks between 12,000L and 50,000L – and even smaller for builds with specific requirements – for those looking for all the advantages of a steel water tank with an antimicrobial water tank liner, at a size more suited to a small water tank.

If you would like a small steel water tank, Pioneer can still try and help you out. Give us a call today to learn more.

Other water storage tank options

Not quite what you're looking for?

Some people may not be looking for a large tank like the ones offered by Pioneer Water Tanks, and may just be looking to have enough stored water in order to get around lawn and garden water restrictions, to use in the washing machine, or simply to save a little money on their water bill.

For these people, who usually still have access to mains water, there are of course many other options for a galvanised or poly water tank, including slimline tanks; designed to fit down the side of your home, underground tanks; designed to fit under decking or under a lawn, or just a smaller round water tank which will fit in the back corner of a backyard without needing a concrete sand pad or clearance around the sides.

If you are still unsure if a round tank or slimline tank would be best for you, simply give a Pioneer Water Tanks representative a call on 1800 999 599, and someone will be able to help you find your rainwater harvesting solution.

Water Tank Accessories

If you find you need a slightly larger amount of water storage than your roof harvesting ability can provide, you may find harvesting off of a shed or garage can help. Alternatively, the below tank roof rainwater harvesting system – the Pioneer exclusive Smart Water Savers – can help you capture water directly from your rainwater tanks roof, thousands of litres more rain water.

A GT110 installed in Perth, Western Australia, would be able to harvest an additional 40,000L of water with the Smart Water Saver attached. Talk about water smart!


These Smart Water Savers, along with the Pioneer Water Tanks Exclusive Aqualiner Fresh® antimicrobial water tank liner, and other standard and optional water tank accessories can be seen below.

Standard Water Tank Acessories

aqualiner fresh layers example antimicrobial water tank liner

1 x Exclusive Aqualiner Fresh® Water Tank Liner

a 50mm outlet with ball valve fire fitting for steel water tanks

1 x 50mm Outlet & Ball Valve

a pioneer water tanks stainless steel leaf filter basket for steel water tanks

1 x  Stainless Steel Leaf Filter Basket or 50mm Inlet

a galvanised steel ladder for large steel water tanks hook on ladder with bracket

1 x Hook-On Galvanised Ladder with Bracket

pioneer water tanks hinged galvanised steel roof access hatch water tank access hatch

1 x Heavy Duty Hinged Access Hatch

a pioneer water tanks 150mm overflow 150mm bellmouth

1 x 150mm Overflow, Downpipe and Flap Valve

a single annode bag sacrificial anode for steel water tank corrosion protection

1 x Set (2) of Anodes

Optional Water Tank Accessories

ball valve outlet for steel water tanks

Fire protection valve and fire water reserve to shire standards

an analogue water level indicator with float valve and weight

Digital or traditional water level indicators

four pioneer water tanks smart water savers tank roof gutter system pieces

Gutterless tank roof rainwater harvesting system

a close up photo of water tank liner protection water tank underlay fabric geotextile underlay

Geotextile underlay to protect liner from damage

SuperSeal water tank dustproofing and vermin protection for water tank freshness

SuperSeal dustproofing condensation strip pack

20/20 Water Tank Warranty

Not an accessory, but certainly included in your water tank price, is Pioneer’s 20/20 Warranty. 

This is a 20 year conditional structural warranty in addition to a 20 year conditional warranty against water leakage, applicable on all rainwater tank models from GT10 – GT280.

Large steel tanks are an investment, and something you only want to buy once in your lifetime, and most of the water tanks built by Pioneer Water Tanks all the way back in 1988 still remain in service to this day, holding water as securely as they did the day they were built.

Pioneer Water Tanks understands that a rainwater tank is an investment that you only want to buy once in your lifetime, and our 20/20 warranty gives you peace of mind that your water storage will last for many years to come.

Here to help your household or business

If you’re want some advice on what water tank size would be best for your home or property, give get in touch with us on 1800 999 599, or by simply clicking here to request a quote for a water tank today; and one of our dealers will be in touch.

Frequently Asked Questions

What are the sizes of water tanks?

With so many different materials, uses, and manufacturers, there are more sizes than it would be realistic to list here.

From small 500L rain barrels or poly round tanks for the home, to the step up with slimline tanks up to 10,000L, to Pioneer’s range of large steel water tanks from 12,000L to 500,000L – and even larger tanks for commercial builds – there is sure to be a water tank size that suits everyone’s needs.

Water tanks from the home can span from 2m to 14m in diameter, and reach up to 3m high.


How do I calculate what size water tank I need?

The best way to calculate what size water tank you require is first to calculate how much water you use annually – at least roughly – and then aim a little bit higher than that. You don’t want to find yourself running out of water.

When it comes to how much water you can harvest, a simple rule of thumb is to multiply your rainwater harvesting roof area by your annual average rainfall, and you will be able to calculate the amount of rainwater you can harvest annually from there.

Which tank is best for drinking water?

There is no one answer to this, as the majority of – if not all  – steel liner tanks and poly water tanks available on the market are made from food grade materials designed to safely interact with drinking water. It would be recommended not to install a concrete water tank for drinking, as they must be entirely emptied to be repaired, and can seep into your drinking water.

Water quality is important to everyone, but particularly those who rely solely on tank water, which is why all Pioneer Water Tanks from 12,000L to 275,000L come with the Pioneer exclusive Aqualiner Fresh® antimicrobial water tank liner, designed to keep your tank water fresher, for longer. 


What is standard water tank capacity?

As mentioned above, there is no true standard water tank size or water tank capacity, as everyone’s needs are different, and all families and households are different sizes and ages.

Of Pioneer Water Tanks wide range of rainwater tanks, however, the GT110 (110,116) model is the most popular, and the one you will most often find installed on rural Australian households.

Where should a water tank be placed?

It is best if your water tank is placed near enough to your water source – be that a shed or your home – and also near enough to where you want the water to come out, so that you don’t require a pump or pump cover which may further push up your costs.

A rainwater tank needs to be located at least 50cm below gutter height for every 100cm away from the downpipe it is situated. For a steel water tank, it is also recommended that you have a sand pad with 100cm clearance on all sides of the tank diameter.