Choosing The Right Material For Your New Rainwater Collection Tank
When shopping for a new rainwater collection tank, it's easy to assume that most tanks are basically the same. However, even something as simple as the materials your new water tank is made from can drastically affect the performance, durability and longevity of a tank -- for better or worse. This article will examine the most common materials used for rainwater tank construction and evaluate their individual strengths and weaknesses.
Concrete
The material of choice for many farming and agricultural applications, concrete water tanks can also be installed in residential settings and are frequently used for rainwater collection. Concrete has a number of properties that make it suitable for rainwater collection purposes -- it is immensely durable, guaranteeing a long service life, and also has great thermal insulation characteristics, ensuring that warm spots in your tank that may lead to algal blooms are minimised. Concrete is an ideal choice if you're collecting rainwater for drinking purposes, as the material does not affect the taste of the water and, with no warm spots, potentially dangerous pathogens will find it difficult to breed within.
Unfortunately, these advantages come at a price, and concrete water tanks are generally significantly more expensive than plastic. Costs can be increased further by shipping, as these heavy tanks will require industrial-grade equipment to transport and install -- a good alternative option is to have the concrete cast and cured on-site, but this may not be feasible for smaller residential projects. You should also make sure that the concrete used contains minimal amounts of fly ash, as there are questions about the long-term toxicity of this substance.
Plastic
Plastic is the go-to option for many homeowners after a small, cheap rainwater tank, and with good reason. These tanks are by far the least expensive option, especially at the smaller end of the size scale, and are widely available. They are also very easy to set up, simply needing a flat, sturdy surface to rest on without any external anchoring or supports.
Plastic tanks are usually made from food-grade polyethylene, the plastic used to make food containers and packaging, so theoretically there should be no problem with installing one for potable water purposes. However, when placed outside in the full heat of the Australian summer sun, these tanks can become extremely hot, and many tank owners are now concerned about unpleasant chemicals leeching from the plastic into the water when hot. This lack of heat insulation also provides little protection for your water against algal and bacterial growth. Plastic tanks are also the most fragile option, especially along the seam left behind after moulding that runs vertically up the side of the tank -- seamless models are available to minimise this problem.
Steel
Corrugated steel rainwater tanks are a familiar sight across many rural areas of Australia and maintain their popularity for a number of reasons; they are strong, long-lasting, cheaper than concrete tanks, and are almost as easy to install as plastic ones. Virtually every steel water tank on the market is galvanised with zinc before sale to prevent rust and corrosion, but despite this special treatment, steel water tanks are generally quite reasonably priced, especially when it comes to large, high capacity tanks.
However thoroughly galvanised a steel tank is, however, it will still succumb to erosion eventually, especially if the tank takes a beating and the zinc coating is scratched. This tends to limit the lifespan of a steel water tank, although there are a couple of ways you can keep it in good shape for longer:
- Choose a stainless steel tank, which are virtually immune to rust. However, these tanks are usually significantly more expensive than ordinary steel or even concrete tanks.
- Choose a steel tank with a plastic polymer lining -- but then you have concerns about chemical leeching to worry about.
For more information and options, talk with water tank suppliers, such as Williams & Jackson.
