Poly vs Steel Water Tanks

Best Materials for Rainwater Tanks

What is the best material for the construction of your water tank? When it comes to choosing a material for your rainwater tank, you have several options, all with a variety of factors to consider. The most common materials for water tank products in Australia are steel and plastic – known more commonly as poly tanks. Less common are concrete water tanks, fibreglass tanks and bladder tanks.

Looking at it from a purely residential perspective – as commercial water tanks have design specifications to consider for each industry – there are a host of differences between poly and steel water tanks that can be features or benefits to some customers and a disadvantage to others.

Each type of rainwater tank has its own set of pros and cons, and even within the same material these can differ when making a comparison of one manufacturer to another, as can things like the price, warranty and dimensions of similar sized water tanks. It is important to consider your personal needs – or that of your customer – before making a decision on the best water tank for you.

Poly Tanks

Poly water tanks, sometimes referred to simply as plastic tanks, are made of polyethylene, a lightweight and UV-resistant plastic which allows for lightweight and durable water storage solutions.

Thanks to their plastic structure, poly tanks are available in a range of shapes, colours and sizes and are easy to install, and thanks to the lack of metal are immune to rust.

One of the biggest advantages of poly water tanks is their versatility, however they aren’t as strong as other materials and if not treated correctly a poly tank can crack or become by impact from a sharp object.

Poly rainwater tanks meet and exceed Australian standards for drinking water and are a food grade product, and are UV-treated so they are resistant to sunlight without the use of any chlorine or chemicals. They are also BPA free.

Steel Tanks

Steel water tanks are most commonly made from Colorbond ® or Zincalume ® steel, and are renowned for their strength and durability, and fitted anodes make them resistant to corrosion.

The major advantage of a steel water tank is its strength and size. They can hold large amounts of water and withstand huge pressure, and can withstand the harshest of Australian weather conditions.

Modern steel tanks are also available in more than the one colour, with a range of Colorbond ® colours available.

Water tanks made from genuine BlueScope steel sheets have the backing of rigorous testing in the harshest Australian environments, meaning you can be sure of the product quality of the material itself.

Concrete and other types of tanks

While less common, other water tank varieties do exist, such as concrete, fibreglass and even stainless steel tanks.

These tanks are typically designed for specific uses, and are engineered for contact with chemicals or high temperatures. 

Stainless steel and concrete water tanks prices are significantly higher than that of steel or poly tanks, and even for large water storage solutions, the cost of concrete water tanks and stainless steel tanks isn’t practical.

Steel vs Poly Water Tanks

When making a decision between poly and steel water tanks, there are several factors to consider. Both are made from food grade materials, and are appropriate for drinking water quality, and provided you live in a location where it doesn’t frequently exceed 40 degrees in the sun, both have a reasonably long lifespan.

Steel water tanks are obviously stronger than poly water tanks, and their integrity in bushfire conditions is a key selling point for many. The liners in a steel water tank are usually only effected by fire above the point the tank is filled to, meaning that fire fittings can still be used after a fire front has passed.

Poly water tank prices are typically more affordable for those looking for smaller water storage solutions – such as slimline tanks or small round garden water tanks – and require little maintenance if treated with care.

While steel water tank prices are higher than poly water tanks up to a point, and then become the more affordable option when you start to need multiple poly water tanks to reach the same capacity. Steel water tanks also typically include your basic fittings and accessories, and only require plumbing, where poly water tanks often need these fittings to be purchased on top of the basic tank cost.

As steel water tanks don’t have any welding, and are held together with screws, rivets and bolts, they are also easier to repair; as a single panel can be replaced or the liner patched up without the need to replace the while water tank.

Using this information to make an informed choice

Despite their differences, both water tanks come with their advantages and disadvantages. If you’re looking for a small water tank, with easy installation, that doesn’t need to provide your entire home with water or protect your property from bushfire, then a plastic water tank may be the best option for you.

If you need a large amount of water storage, and have the space for a large base to serve as a tank pad, and need reliable access to water supply from your water tank year round, or for bushfire protection purposes, then you’re likely more suited to a steel water tank. The fact steel water tanks are more affordable at larger capacities may be enough to make your decision.

Your local shire or council may also have requirements about the tank materials, styles and sizes of water tanks that can be installed on your site, which may end up making the decision for you.

Have more questions about Poly vs Steel Water Tanks? No worries!

If you’re still unsure about the best value water tank for your home or property, get in touch with Pioneer Water Tanks today by calling us on 1800 999 599 or filling out our contact form with your name, area and any other comment you think may be helpful, and one of our dealers will be in touch with you shortly.

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