Rainwater storage tanks have become another option in water conservation efforts all around the world. As rainwater is collected and then stored immediately, rainwater conveyance systems, including rainwater tanks, are a staple fixture in both private residences and industries for a variety of uses. Two of the most common materials used in creating rainwater tanks come in the form of fiberglass and steel. In here, let’s take a look at the two materials used in rainwater tank design.

Is fiberglass for you?

Fiberglass rainwater storage tanks have many benefits for different types of consumers. This type of storage tank is made up of fiber-reinforced plastic and fiberglass materials to cope with the maximum storage of rainwater. Fiberglass is a relatively inexpensive material compared to carbon fiber and is stronger than many metals. Additionally, fiberglass is a nonmagnetic, non-conductive material that can be molded into complex shapes.

Fiberglass rainwater tanks are a very lightweight option for consumers who are looking to collect and store rainwater for a number of uses. Since these tanks are made from a combination of resin and fiberglass materials, fiberglass tanks are virtually corrosion-resistant, except for the installations on which the tanks are built. Another benefit of fiberglass is that these types of storage tanks are not easily damaged by saltwater, especially those in coastal towns.

In terms of use at home, fiberglass is a cheap option to more expensive rainwater storage tanks of similar capacities like concrete or steel. Since fiberglass is a lightweight yet sturdy material and could be molded into different shapes, fiberglass rainwater tanks are a space-saving feature that could easily be installed in home or industrial rainwater collection systems for medium- to large-scale rainwater storage.

What about steel?

One popular material used for storing both freshwater and rainwater is steel. Older steel storage tanks were made from galvanized steel, which is corrodes easily. Galvanizing steel later causes an excess of zinc to leach into the water supply. While the water is still safe for drinking, the zinc could affect the taste of stored rainwater and consumers might have to take additional steps to eliminate the zinc aftertaste. Modern steel tanks, however, are now made with rust-resistant coatings or lined with food-grade polymer to increase the steel water tank’s life span and usability.

Steel rainwater tanks are primarily acquired for its huge water-holding capacity, where the stored rainwater could be used in have heavy work like farm irrigation, hotel cleaning and maintenance, livestock, household chores, and, with the right disinfectants, also for drinking purposes. Although more expensive than fiberglass rainwater tanks, steel tanks last for a long time, sometimes outlasting their owners, with minimal maintenance or repair work. Most suppliers offer 20-year warranties for the steel material. But for the manufactured product itself—i.e., the rainwater tank—suppliers provide 10-year warranties, so make sure to read your warranties.

The design of these water storage tanks varies a lot among customers. There are lots of models and capacities available for different storage purposes. Small steel rainwater tanks that could hold as little as 300 liters and as much as 7,000 are perfect for private residences. Bigger-capacity tanks that could hold as much as 39,000 liters are perfect for farmsteads or small businesses highly reliant on water such as a laundromat or a car wash.

Should I go for fiberglass or steel?

Although rainwater tanks made from either material are perfect for storing rainwater, there are a lot of differences between the two materials that could be a benefit or a drawback to the consumer.

Fiberglass is a very stiff or rigid material. This means the tank walls could be molded relatively thin; however, this rigidity means that fiberglass rainwater tanks tend to be brittle as well, oftentimes prone to cracking or leaking in changing temperatures. As fiberglass rainwater tanks can be made with very thin walls, fiberglass allow more light entry compared to other tanks of similar sizes. This means the tank is prone to promote algal growth, which means the tank must be installed indoors or lined with a black covering or a painted exterior to prevent this issue.

On the other hand, steel rainwater tanks can be very expensive. However, most suppliers include affordable payment schemes and pro-rata warranties so you could maximize the usage of these types of tanks. Compared to fiberglass rainwater tanks, steel tanks often take up considerable space on a property. This means steel rainwater tanks may not be ideal for properties with less area. Although older steel tanks are prone to corrosion, newer ones are lined with plastics or coated with anti-rust materials to extend their life span.

Choose a fiberglass rainwater tank if . . .

  • you want a versatile storage option
  • you want an inexpensive option to store collected rainwater
  • you have a small property or are willing to install the tank indoors
  • the stored rainwater serves as backup to mains water

Alternatively, choose a steel rainwater tank if . . .

  • you want to invest in rainwater collection and storage in the near future
  • you have a dedicated space on your property for the tank and its installations
  • your business or home is dependent on rainwater as a main water source

Whichever type of rainwater tank you choose, both will do you good in the water and costs you save, not to mention your help in saving the environment. Both may appear to be substantial short-term investments, but what you pay initially pays for itself in the long term.