If the water storage tank is designed for human consumption, the materials used must comply with the potable-water standards.
New water tanks can occasionally introduce distinct tastes and odors. For example, galvanized tanks may initially give water a metallic taste due to excess zinc leaching, and new concrete tanks may have a high pH caused by excess lime, potentially resulting in a bitter taste. Water from other types of tanks tends to be slightly acidic.
Plastic (Poly) Tanks
In Australia, the most common materials for water storage tanks are plastic or poly water tanks, typically produced using the rotational molding process. Plastic tanks and liners must be made from food-grade materials that meet potable-water standards if they are used for human consumption.
Polyethylene (Poly) is durable and non-corrosive. Polyethylene water tanks will not rust or corrode like metal tanks throughout their service life. These tanks are lightweight, easy to handle, constructed as a single piece without joints, and can be recycled once they reach the end of their useful life.
Steel Liner Tanks
Steel liner tanks are steel water tanks with a poly liner that holds the water. The poly liner prevents water from coming into contact with the galvanized, preventing corrosion, and is ideal for storing potable water. If the water is to be consumed, the poly liner material must meet potable-water standards.
Main advantages of steel liner tanks include the liner’s water-holding capacity and the modular steel structure, allowing assembly on-site and being less expensive than comparable-sized concrete tanks.
These tanks are made of galvanized steel, requiring sacrificial anode replacement every 5 years for effective corrosion protection.
Steel Water Tanks
Most water storage tanks materials in previous generations were made of galvanized steel, which has limited corrosion protection. Galvanized steel has a lower corrosion resistance than polyethylene. The introduction of steel tanks with a poly liner is another innovation.
If there is direct contact between the water in the tank and the zinc wall, this may be leached into the tank and can occasionally affect the taste of stored rainwater, but it poses no health risk. Galvanized water tanks should ideally be flushed before use.
Galvanized steel is the primary material used in steel tanks. Galvanizing is the process of applying a zinc-based coating to metal. These galvanized sheets are then soldered together or sealed with a silicon sealant.
Stainless Steel Tanks
Water tanks can also be made from stainless steel, resistant to rust and corrosion, unlike traditional steel tanks. However, stainless steel tanks are significantly more expensive than standard coated steel tanks and plastic tanks.
Concrete Tanks
Concrete and ferro-cement water tanks are extremely strong and long-lasting, typically installed underground. New concrete water tanks may impart tastes and may leach lime, requiring flushing before use.
Concrete water tanks are typically the most cost-effective underground solution, ideal for covering with load-bearing lids and fitting beneath driveways or other structures. One common complaint is cracking and leaking, which can be repaired if the tank can be drained. In some cases, a plastic liner is required.
The concrete tank standard allows for some leakage, whereas the plastic tank standard does not allow for any leakage.
Fiberglass
Water can be stored in fiberglass tanks (or GFRP Glass Fiber Reinforced Plastic). The interior surface of these tanks must be coated with a food-grade coating, cured before sale.
Fiberglass has the advantage of being very stiff, allowing relatively thin tank walls to manage water pressure. The disadvantage is that it is brittle and prone to cracking and leaking.
Most fiberglass tanks contain a resin mixed with a catalyst or hardener and glass fibers sprayed onto a mold. Tanks may vary in the manufacturing process, and precautions are needed to prevent algal growth, such as sealing with a black covering inside or painting on the outside.
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Our friendly and experienced customer service team is here to help you! Contact Raven Tanks at 1800 907 834 or [email protected].
