In an age where evidence of human-caused environmental damage becomes more obvious and unnerving every day, more and more households are trying to do their part to save valuable resources and energy, and installing a rainwater collection system to supplement your home's water needs is an effective and relatively inexpensive way to go about it. Of course, every rainwater collection system needs a water tank to store the accumulated water, and slimline tanks are a very popular choice for their ability to fit into compact spaces.

However, while some slimline tanks are made from plastics, others are made from coated steel, and choosing between the two can be more challenging than you might think. Each material has its own advantages and disadvantages, so you should familiarise yourself with their properties before deciding which type of slimline tank is best for your needs.

What are the advantages and disadvantages of choosing a steel slimline tank?

As you can imagine, steel slimline tanks are the tank of choice if durability matters to you, and a well-made steel tank can be relied upon to safely store your water even when faced with heavy impact damage from falling branches, errant cars and other objects. Despite this strength, they are fairly lightweight when compared to most plastic tanks, as the extra strength of the metal allows for thinner walls. This can make steel slimline tanks considerably easier to transport and install if you intend to do so without professional assistance.

Unfortunately, while any good steel slimline tank is coated with thick, durable paints and rustproof treatments both inside and out, these coats are not invulnerable and will degrade over time. This time frame can stretch from years to decades depending on the tank you choose, but once the coating wears away your steel tank will quickly fall victim to rust. You should also bear in mind that steel tanks may be more expensive than plastic equivalents, and they will need some kind of internal food-grade coating if you intend to filter your collected rainwater into potable water.

What are the advantages and disadvantages of choosing a plastic slimline tank?

Plastic slimline tanks are made from tough, durable thermoplastics, and while they lack the immense durability of steel tanks they are still capable of taking a heavy beating. They can also be more suitable for outdoor, unsheltered locations, as they will never fall victim to rust. Despite these advantages, plastic slimline tanks tend to be considerably cheaper than their steel cousins, making them ideal for budget rainwater collection system builds or systems that require multiple slimline tanks.

However, the main problem with plastic slimline tanks is that they are very difficult to repair if they are unfortunate enough to suffer severe damage, and will generally have to be replaced; this is in contrast to steel tanks, which can generally be welded and plated if they spring a leak. Plastic tanks also tend to absorb more heat if placed in direct sunlight, which can promote the growth of bacteria and algae in your collected water; choosing a lighter-coloured tank can help alleviate this issue.