Plastic water tanks vs. Steel Water Tanks. This week we’re here to talk about all the nitty-gritty details when it comes to choosing the perfect water tank for your end-use application. We’re going to talk about the good, the bad and the ugly.

End-Use Applications of Storage Tanks

When you are looking at buying a storage tank, it is important to note that there are different storage tanks in the market and have various end-use applications. Therefore, you need to do your “homework” and ensure that you are getting pricing on the right type of tank. Some tanks are made for chemical storage and can be used to store various chemicals and waste, while others are made specifically for water. As a general guideline (not a hard-and-fast rule), you can match end-use application with the following materials:

  • Plastic (Polyethylene) Tanks – Most commercial tanks that are sold in shops are for domestic purposes like backup water storage.
  • Steel (Zincalume) Tanks – Perfect for water storage for homes, businesses, and complexes.
  • Steel Fusion Bonded Epoxy Tanks – Perfect for industrial use (Chemical Containers, Sewage, water treatment plants, etc.)
  • PosMAC – Fire Resistance material, therefore, this water tank will not be corroded or damaged by fire and extreme weather conditions. Perfect for safely storing flammable liquids.
End-Use Applications

While there are many materials that tanks can be made of, we will be discussing the two most common domestically used water storage tanks: Plastic (Polyethylene) Tanks, which we will simply refer to as plastic tanks and Steel (Zincalume) Tanks, which we will be referring to as steel tanks.

So let’s get down to the dirty details of each of these water storage containers:

Plastic Water Tanks:

Plastic water tanks are common for domestic use. Most tanks are made out of Polyethylene.

” Polyethylene or polythene is the most common plastic. As of 2017, over 100 million tonnes of polyethylene resins are produced annually, accounting for 34% of the total plastics market ” – Wikipedia

Advantages of Plastic Water Tanks


Plastic Water Tanks are significantly lighter than steel tanks. This is due to the fact that the material that they are using is plastic, which is lightweight in itself.

Colour Options

Because plastic is such a versatile and widely used material, there is a wide range of colours to be chosen from when you purchase a plastic water tank.


Plastic is affordable (for the most part) due to the fact that it is widely used and readily available.

15-25 year Lifetime

Most Plastic Water Tanks claim to last for 15-25 years (depending on which company you buy from). But the warranty or guarantee only lasts between 3 – 6 years (depending on supplier/manufacturer)

Plastic Tank

Disadvantages of Plastic Water Tanks

While plastic might seem like the obvious first choice initially, when you look at the disadvantages, you might change your mind fairly quickly.

Not Eco Friendly

As we all know, plastic takes (generally) between 10 – 1000 years to degrade. Because a plastic tank is so big and thick, we can assume that the number is on the far end of that scale when it comes to how long it takes to degrade.

Furthermore, plastic tanks can not be made from recycled materials due to health and safety laws. Additionally, once your tank has outlived it’s usefulness you can try to re purpose it, or cut it up and send it to a recycling plant. Taking it to a recycling plant is the responsible thing to do, but this still contributes to the massive plastic waste epidemic we are facing worldwide.

Colour Fades

While you do have a wide range of colours available when initially purchasing your tank, the colour can start to fade after a few years of direct sunlight and exposure to various weathering factors.

Unfortunately, it is a fat that UV rays can play a significant part in the damaging and fading of the plastic tanks. While there are certain measures put in place by manufacturers (when dealing with reputable water tank manufacturers) to prevent this from happening, it is not a 100% gaurantee that you water tank will stay crisp and strong with prolonged exposure to direct sun.

Heated Water

Black and dark blue plastic water tanks are notorious for heating up the water in the tanks. Why is this a problem? Firstly, when using water directly from the tank for household use, you will usually have luke-warm to warm water flowing out of the cold taps. Additionally, and more concerning, is the fact that higher water temperature is conducive to algae growth.

When you are using the water in your storage tank for drinking water, this could be harmful.

Difficult to transport

Plastic water tanks are lightweight, but that does not mean that they are easy to transport. Most water tanks are manufactured in one piece, meaning that there are no seams etc. While this is beneficial to prevent leaks and other complications it may post as a disadvantage when it comes to transport.

If you are purchasing a water tank that is 10 000 litres, you must be aware of the fact that it won’t be a small tank. In fact, you might struggle to load it onto a bakkie and will require a small truck. Furthermore, the bigger the tank, the more hassle it is for transport. Some of the plastic tanks for agricultural and industrial use is are so big that they require an “abnormal load” sign and special precautions due to the height and width of the water tank.

Steel Water Tanks

Steel water tanks have been around for decades, but don’t think that they are still the same old water tanks. As time and technologies have progressed, so have steel water tanks.

The revolutionary advancements have allowed steel water tank manufacturers to go above and beyond to supply customers with the highest quality water tanks.

Zincalume was first discovered and released into the market in the 1970s, and since then it has become a staple for any steel tank manufacturer. Let’s look at some advantages and disadvantages of Zincalume (steel) tanks.

Advantages of Steel Tanks


Zincalume is a compound consisting of 55% aluminum, 43.5% zinc, and 1.5% silicon.

This compound is revolutionary as it increases the lifespan, makes it more durable and, makes it corrosion-resistant. In fact, tanks made out of Zincalume is four times more corrosion-resistant than galvanized steel.

“We have a warranty of 20 years pro-rata on our Zincalume Water Tanks”


That is how confident we are in our steel water tank products and it’s durability. While the warranty is for 20 years, these tanks will last well over 20 years without any problems.


We know what you’re thinking: Steel tanks are cool and everything, but they are probably very heavy. And we’re here to tell you that you are wrong.

Our steel tanks have all the benefits of heavy steel reinforcement, without the disadvantage of a massive amount of weight. These tanks are surprisingly lightweight and easy to maneuver and install.

Size Options

The sizing options for steel water tanks are virtually limitless. Because the steel water tanks can be manufactured in various ways and with various steel materials like:

  • Panels of Steel with nuts and bolts
  • Corrugated Steel

This allows the manufacturer to build tanks from 1000 liters up to 2 006 000 liters!


Steel water tanks won’t fail you when it comes to extreme environments. Whether you are in a place that is scorching hot, freezing cold or somewhere where fires are a common occurrence like farms and other high-risk fire areas.

Steel tank manufacturers like Aquadam will have a specially designed steel tank to suit your needs.

No need to stress about wind speed and the flexibility of a steel tank. They are made to uphold their firmness of shape and mechanical strength, they will not buckle, bulge or blow away in extreme weather or under immense water pressure.

Simple and fast repairs

So let’s say you have a minor, or major leak in your water tank for some unknown reason. You don’t have to stress about the repairs, as it is usually an “easy fix”.
Because steel water tanks are manufactures in “parts” with bolts and steel plates, or corrugated steel, it is relatively painless to do a repair job.

Easy to Transport

Once again, due to the fact that the steel tanks are manufactured piece by piece, they are easy to transport. At Aquadam, we can transport our water tanks anywhere in the world by making use of the “flat-pack” method to reduce transport costs and make it easy to get your water tank from point A to point B.

Steel Water Tanks

Disadvantages of Steel Water Tanks

Steel water tanks have some amazing advantages and benefits to you as a consumer. But there are one or two disadvantages to these tanks:

Colour Options

While there are a few options to choose from when you compare the color selection of plastic tanks to the steel water tanks, most of the time the plastic tanks have a wider selection. This does not mean that the Steel tanks have a very small selection. These water tanks can be made in any of the following colours:

Rainwater Steel Tank Colours
These colours are available on our Rainwater Harvesting and Home tanks.

But if the plastic tank’s color is going to fade and become brittle in the next 20 years, while the steel water tank has a warranty of 20 years, is it really such a big disadvantage?

Some metals can’t mix

Ensure that you are aware of which chemicals, metals, and liquids cannot be stored or come into contact with your Zincalume tank. As an example from Rainharvesting.com, the effects can be quite severe:

“Water traveling from the ZINCALUME® roof to the galvanized tank caused the tank to rust and even collapse. This occurred because the process of galvanic corrosion, whereby different metals are joined together by a medium such as water, accelerates corrosion. In such situations, the less “noble” metal corrodes and rusts – and that meant the galvanized tank fell victim.”

While this is very far-fetched, and not likely to happen, this is a disadvantage of some steel tanks. They do not play well with a hand full of other metals and materials.

In conclusion to Plastic vs. Steel Water Tanks

Steel water tanks are far superior to plastic water tanks in:

  • Strength
  • Versatility
  • Durability

Steel tanks are not limited by specific molds, shapes and sizes. Anything is possible when you are manufacturing these water tanks from scratch, which is exactly what we do at Aquadam.

Looking for more information on our Steel Tank product range? Feel free to contact us