Below are answers to some of the most common questions we get asked about poly lined steel water tanks.
The rainwater tank you should choose will depend on your rate of water usage, the amount of rainfall your area receives and your available collection area.
An average four person family living in a two bathroom home uses approximately 90,000 Litres of water per year (not including lawns or gardens) and has a collection area of around 300 square metres.
In an location that receives an average 500 millimeters of rain per year a 300 square metre collection area, you have the ability to collect up to 150,000 litres of water per year. Generally you will not require a tank large enough to collect the total amount of rainfall per year, as usage will reduce the amount stored for future rain collection
Average rainfalls for different areas in Australia can be found on the Australian Bureau of Meteorology website
The main cause of corrosion of a water tank occurs when condensation builds up between the liner and the internal surface of the tank shell.
Zincalume® tanks use a sacrificial anode to protect the steel shell. For an anode to work correctly, a circuit needs to be created between the sacraficial metal (the anode) and the material to provide protection. Unfortunately, the ground the tank is built on is not a good conductor and the cathodic protection system is almost always incomplete. Anodes work very well on boats because the sea water causing the corrosion is a relatively good conductor that completes the circuit.
Aquamate uses a Z450 galvanised coating on its water tanks. Aquamate’s Z450 galvanised coating is more than three times the thickness of AZ125 Zincalume coatings, making it better suited to the conditions created within a water tank.
Aquamate uses Zincalume® sheeting for our tank roofs as there is sufficient airflow above and below the sheeting. This provides a different environment for the steel and zinc/aluminium coating offers better protection from corrosion under these conditions.
When selecting the best liner material to use in a water tank, the most important considerations are flexibility, elongation (“stretch-ability”) and chemical resistance.
Reinforced liners consist of an open weave mesh with a thin waterproof plastic coating on each side. Reinforced liners have high strength and dimensional stability and work well in high stress applications like tarps and grain covers. In a water tank, the stress is taken by the steel tank shell and the liner “grows” as the tank fills and empties during use. Aquamate’s mono-filament liners have high levels of flexibility and much greater ability to stretch than reinforced liners, making them better suited to long term use in a water tank.
Aquamate’s polyolefin liner material is based on a flexible low density polyethylene, unlike PVC which is naturally rigid (think storm water pipe). PVC needs chemical additives to make it flexible enough to be used as a liner inside a water tank. Over time, the chemicals used in PVC leach into the water, turning the material rigid, which leads to cracks and ultimately leaks in the liner.
If you think your water tank may require council approval because of your area, encroachment near boundaries or other structures, Aquamate recommend that you seek advice directly from your local council authority.
In the event that you do require council approval for your rainwater tank, Aquamate will be happy to liaise directly with council regarding the details of your tank on your behalf. All we need is your planning approval number.
Do you have a question about water tanks that doesn’t appear on the list? Contact us using the form below and we can answer it in person.