Rainwater collection is one of the most sustainable ways to harvest a water supply to use in and around your home. Collecting rainwater is popular for both drinking and non-drinking purposes, such as simply watering the garden.
The water tank in Australia has long been an obvious necessity in rural and off-grid areas. However, the need has not been so obvious in urban Australia until recently.
Now, a combination of record populations, high water usage, and some of the worst droughts in generations has seen authorities change from opposing urban water tanks in Australia, to welcoming, encouraging, and even mandating tanks in several jurisdictions.
Not only is government regulation of water tanks in Australia moving towards a water tank on most new homes, but there is a rapidly increasing number of existing home owners are installing water storage tanks as well.
Of course, the most obvious component of any good rainwater harvesting system is going to be the water tank. The water tank, as it is so aptly named, is the large container in which your rainwater is stored before it is used in and around the home.
Water is an extremely important and valuable resource for sustaining life, so we are pretty lucky that it simply falls from the sky. However, it is a bit more complicated than just sticking a few barrels in the backyard and waiting for Mother Nature to do her thing. For this reason, we’ve put together this extensive guide on everything there is to know about rainwater harvesting tanks.
The Main Characteristics of a Water Tank
In terms of recognition, water tanks are pretty unmistakable. Typically, water tanks for rainwater are not easy to miss on someone’s property. This is because they are almost always larger than any vehicles in the driveway, and are positioned so that they can easily collect water.
Water Tank Size Guide
First, let’s take a look at the different size water tanks that make the most sense for Australian homes. Although it is true that the size of the water tank is likely a result of budget and space availability, there are a few ways to calculate approximately how large of a tank your home will need.
A Simple Rainwater Harvesting Calculator for Australia
To get started, take a look at Australia’s Bureau of Meteorology’s Website. Here you can see the exact amount of rainfall that your area receives on average. Next, estimate the area of your roof. On average, Australian suburban homes have roofs that are roughly 200 square meters. Simply multiply the size of your roof by your area’s annual rainfall, and you will get a rough calculation of how many litres of water you can potentially collect over the span of a year.
200 (square meters of roof area) x 1309 (average annual rainfall of Sydney in mm) = 261,800 litres per year.
or if you prefer a monthly look…
200 (square meters of roof area) x 109 (average annual rainfall of Sydney in mm) = 21,800 litres per month.
There is obviously lots of fluctuation between months throughout the year, so an average monthly number will underrepresent some months and overrepresent others. Nevertheless, for planning purposes, these calculations can give you a pretty good rough idea of how much water you have to work with.
In terms of usage, Australian’s use about 250L of water per day. So if your water tank is going to supply everyone in the home’s water, you must take 250L of water per person into consideration. Once it’s installed, you will never be upset about having too much water storage capacity, so if possible, it is always advised to err on the side of caution and oversize your tank.
Water Tank Shape Options
The shape of an ideal water tank is also highly determined by the available space on your property. There are two main shapes for rainwater tanks: round and slimline.
Round tanks are well, round. They are the most popular and easy to identify. Usually, a round tank is cylindrical and is built to a height roughly equal to its width. In some instances, a “squat” tank can be installed, which is a round tank that is much wider than it is tall. Squat round tanks are primarily designed to go under decks or to fit strategically on the property.
Wherever ground space is scarce, many Australian homes will install a slimline tank. Slimline tanks are classified as tall and skinny, designed to take up a small footprint while still providing plenty of rainwater storage.
When drawing up the best solution for an individual property, creativity does not have to be limited. Tanks come in all shapes and sizes, including rectangular, oval, and modular. Just remember, each shape has its own pros and cons.
Consider Where Will Your Tank Will Be Located
Obviously, one of the biggest factors in selecting the right water tank for you is determined by where it is going to be on the property. Specific spatial constraints will limit your size and shape options.
Above Ground Water Tanks
First, above ground water tanks are very popular for rainwater storage, because they are relatively easy to install and maintain. In some areas of the country, close-proximity neighborhoods may limit the size of an above ground water tank. For homes free of restrictions, the possibilities are endless for installing an above ground water tank for rainwater collection and storage.
To install an above ground water tank, a hefty foundation is required. Keep in mind that thousands of litres of water is equal to tonnes of weight. If your water tank is built on faulty foundation, then that can lead to serious damage to your property, your neighbors’ property, and the people in the area.
In order to get started installing a ground water tank, most people level the soil surrounding the proposed area and then add a layer of sand. Like your drink at the beach, sand makes it easy to level the liquid storage for safe and optimized performance.
Of course, in areas with heavy rainfall, the sand beneath the tank may also be washed away. If this is the case, many people choose to install their above ground water tank on a concrete surface. For even more security, many people choose to add additional fastening components along the body of the structure.
Unfortunately, a drawback to water tanks being installed above ground is that they are fully exposed to the elements. Water tanks can be damaged from heavy weather storms, chronic sun exposure or other external forces if they are left unprotected in critical conditions.
Below Ground Water Tanks
As you may imagine, the alternative to installing a water tank above the ground is installing a water tank below the ground. Below ground rainwater collection tanks are especially popular in new home construction projects. As it may be more difficult and not worth the while to dig an enormous hole in your yard, below ground water tanks work best in specifically designed instances.
There are many advantages to installing your water storage tank below the ground.
- For starters, it is very protected. The likelihood of your water tank becoming damaged below the surface of the earth are slim to none.
- Secondly, you are saving a lot of valuable space with an underground water tank. If you are doing a major excavation (like adding a garage or redoing your driveway), you may want to consider adding an underground water tank to the project. In doing so, less of your yard will be occupied by an enormous, an objectively unattractive barrel.
- Lastly, many residential areas have restrictions on size and height of permitted water tanks in Australian neighborhoods. Installing your water tank completely or even partially underground can help you bypass some of the setbacks brought on by local jurisdictions.
Ultimately, a below ground water tank may seem like a hassle to install and maintain, especially given the fact it is a bit more expensive. However, with a few advantages and the occasional city code requirement, underground rainwater storage tanks are an extremely practical option for sustainable living.
Water Bladder Tanks
Finally, bladders are the third water tank option. A water bladder tank is somewhat of a hybrid system between above and below ground storage, because they are normally only installed below decks or floors. They are not dug far into the ground, nor designed to withstand the elements outdoors. For these reasons, they are popular for homes on stilts or with raised components.
A bladder is easily identified as it is not a fixed volume. Instead, the storage container expands as it becomes filled with rainwater. Of course, bladders have a maximum volume that they can’t be filled beyond.
Bladders are handy in using otherwise unoccupied space to store water for later use. They are flexible and don’t leave you with a giant tank in your yard. However, they are more expensive to install and generally require more maintenance than simple above or below ground water tanks.
Wet or Dry System for Rainwater Collection
Beyond the tank, the other very important thing to consider in your rainwater collection system is how your will be collecting the rainwater itself. There are two main classifications of rainwater collection: wet or dry systems.
Dry Rainwater Collection Systems
In a dry system, there is a small amount of piping connecting the rainwater collection system on the roof to a water storage tank. Here, everything travels downhill. The water falls from the sky, heads to your gutters, and then travels down a simple, sloped pipe to the water tank. It is called a “dry” system because when the rain stops, the systems components are completely dry. Every bit of rainwater is sent directly to be stored in the tank, with none left behind.
Unfortunately, dry systems are not always possible. The direction and location of your gutters and tank may limit direct, downwards paths from being installed. Additionally, tanks located large distances from the collection area or paths obstructed by buildings, plants, or other hazards may not be able to install a simple, dry system. Instead, a wet system can be used to transfer rainwater to your tank.
Wet Rainwater Collection Systems
In a wet system, the pipes connecting the rainwater to the tank are below the height of the storage container. Here, water remains in the pipes until it reaches a critical volume that spills over into the water storage tank. Wet systems can be installed underground, but need to be reinforced to protect against subsurface insects and critters. Additionally, wet systems need to be flushed more often, in order to thoroughly clean the mesh components blocking soot or debris from reaching the water tank.
Water Tank Material Guide
Okay, now that you’ve got your tank shape, size, and location all figured out, it is time to choose the best material. Water tanks for rainwater systems are not limited to any particular type of material, however, the most popular choices are: plastic (poly), aquaplate, steel, & fiberglass.
Plastic (Poly) Water Tanks
Plastic water tanks are among the most popular water tanks for rainwater storage with a large variety of colors, shapes and sizes. The most common plastic water tanks are made of polyethylene or polypropylene, which are often simply referred to as “Poly.”
Financially, poly water tanks are going to be the most affordable. They are not made of a very expensive material and are a bit lighter, and therefore less expensive to install than other types of tanks. Plastic tanks are highly resistant to saltwater, and are therefore a popular choice for coastal inhabitants.
Overall, a poly water tank is going to be durable and resistant to most potential damages it may incur through its lifespan. They can be easily repaired with most plastic fabrication systems, with many companies offering warranties and repairs free of charge. Of course, heavier damages may put a poly water tank completely out of commission.
By and large however, a poly water tank is the best fit for most people, because of their lower cost, their reasonable durability against environmental factors, and ease of transportation and installation.
Unfortunately, plastic water tanks may not the best choice for a sustainable lifestyle. The poly material slowly degrades in direct sunlight to the point where the tank is eventually useless. Due to its material, poly tanks cannot be recycled that effectively and often wind up in landfills. During its daily use, poly water tanks also may lead to significant water stagnation, as there is rarely a water/air interface built in.
Aquaplate (Galvanized) Water Tanks
Aquaplate, otherwise known as galvanized or metal, water tanks are a great option for storing collected rainwater. Aquaplate tanks are generally made with flat rolled or corrugated metal and an inner plastic lining. The waterproof coat on the tank’s interior helps prevent corrosion, while the reinforced outside material protects the entire system from the elements.
Although they are usually more expensive than plastic tanks, aquaplate water tanks come with a number of distinct advantages. To start, galvanized tanks are designed to be durable and usually last between 25 and 40 years. Although they are more difficult to repair, aquaplate water tanks rarely succumb to any sort of damage as they are built to be durable and robust.
At the end of its life, a galvanized water tank may start to leak in corroded areas. The materials are still very valuable however. Taking your ancient tank to a metal scrap yard is a great way to repurpose and possibly profit from your defunct storage system.
Stainless Steel Water Tanks
Like in any application, stainless steel marks a certain level of durability and performance in a rainwater storage tank. Stainless steel water tanks come at a premium price, but can also deliver one of the best overall life cycles for rainwater harvesting.
First, let’s note that stainless steel is 100% recyclable. If you are aiming for a sustainable lifestyle, stainless steel is a much better choice than galvanized or poly tanks that are made with materials that cannot be reused. Stainless steel does not corrode rapidly and is therefore very valuable for many applications.
In general, stainless steel water tanks are a bit smaller than their poly and galvanized counterparts. They are extremely strong and durable, but still very easy to repair if necessary. Stainless steel can be repaired with a simple sealant or with a welded patch, whereas an aquaplate tank cannot be welded due to its plastic components at risk of melting.
Fiberglass Water Tanks
If you are in a particularly hot area, then you may want to consider a fiberglass water tank, especially if you are installing your storage above ground. Fiberglass water tanks are resistant to rust and chemicals that poly and steel tanks are very vulnerable to. Although they are a bit more expensive upfront, a fiberglass water tank is almost guaranteed to deliver a longer lifespan.
Unfortunately, the compounds that create fiberglass bonding make it a potential health risk if in direct contact with the water source. For this reason, a plastic lining (like in that of an aquaplate tank) is added to the interior.
It is also good to know that fiberglass water tanks are very resistant to damage. This is especially helpful, because they are very difficult to repair if they do become damaged. Specialized fiberglass labor is sometimes hard to come by. With this in mind, the end of a fiberglass water tank’s life is usually found in a landfill. Obviously, it may not be the best solution for sustainability, but may be the only option for areas with extreme temperatures.
Water Uses for Rainwater Tanks Systems
Many Australians with rainwater tanks choose to filter their rainwater and use it inside their homes, just like normal. Simply, turn the faucet and there you have it, fresh water straight from the sky. Beyond this, rainwater is also very common for agricultural, industrial, and functional instances in which the quality of the water is not as critical as it would be if you were using it for personal consumption.
Ultimately, here are the main household uses for rainwater tank systems:
- Drinking water
- Household use (cooking and cleaning)
- Waste water
Depending on your specific water needs, different systems and components can be used in order to optimize your rainwater collection and needs. Below, we will outline a few of the most popular specific-use and individually beneficial water tank add-ons.
Post Tank Filters
Although most rainwater collection systems use a “pre-tank” filter in order to store the highest quality water possible, some tanks also include a “post-tank” filter. Here, the water is filtered after it has been stored in the tank, directly before it is going to be used. This enables the absolute highest quality water possible and helps bring natural rainwater to Australia’s potable water standards.
Thanks to our good friend gravity, most water tanks dispel the water at the bottom of the storage container to be used first. Unfortunately, this means that water tanks are often pumping out the oldest, most polluted water in the entire system.
To combat this, a water pickup can be installed. A water pickup is a specially designed floating device that uses a hose to draw water from the cleanest supply points. Water pickups rise and fall with the tanks interior water level, always sending the cleanest water possible to your home.
Additionally, gravity limits the direction in which water can be dispelled from your water tank. For this reason, pumps can be installed to direct your rainwater to any desired location (although they may not be necessary if you are only using rainwater for irrigation).
Pumps are great and often necessary, however there are a couple drawbacks to installing one:
- First of all, they can be quite loud. For the sake of your sanity (as well as your neighbors), pumps need to be strategically located so that they can operate at full capacity without excess noise pollution.
- Secondly, pumps need a fuel source in order to function. This means added electricity costs for directing your rainwater.
If you’re interested in a hybrid rainwater and city-water system for your household water use, you can utilize a water changeover system for the best overall in-home experience. For the most part, sustainably minded homeowners will try and run their days off of exclusively rainwater. However, this is not always possible, so it is good to have a backup that is still connected to an external water source (like that provided by the city).
Although they cost a bit to install, water changeover systems are perfect for saving money and sustainably sourcing your home’s water. Some robust systems use hydraulics to operate with manual switches, whereas other modern changeover systems can be controlled with a remote controller or even a smartphone app.
High Quality Water Tanks Factors and Contributors
Although it may be tempting to cut costs with cheap components, installing a high quality water tank is the best way to ensure a long lifetime of storage.
Thankfully, a Standards Australia certification is a foolproof way to ensure a high quality water tank. With a rigorous check and safety inspection, high water quality tanks are measured by a strict set of standards. This includes:
- No side seams (tanks should be constructed as one piece)
- Locating the manufacturer’s serial number
- Assuring tank thickness (>4.5mm)
- Assuring high quality materials
- Protection against UV rays (UV8 level)
- Quality control efforts on manufacturers
In addition to purchasing a superior product, unlicensed and cheap water tanks should be avoided as they usually have shorter or nonexistent warranty periods. Storing thousands of litres of water on your property has the potential to seriously damage your property, so a high quality tank is best to ensure absolute peace of mind.
Water Tank Accessories
Of course, with a rainwater collection system there is more than just the tank and the pipes. There are a number of different accessories that can be used to keep your rainwater free of any damage due to overflow, debris, or other potentially harmful influences.
Whereas it is rare that every system will need all of these accessories, here are some of the most common common additional components of a rainwater collection system:
- Water level gauges/levitators
- Outlets and overflow pipes
- Leaf guard
- Rain guards
- First flush diverters
- Pre-tank filters
- Tank vacuums
Beyond this, you can further optimize your sustainable lifestyle with specifically designed appliances such as washing machines and toilets and that can be operated with rain water.
Although some people prefer to “learn by doing,” it can be extremely useful to talk to an expert when designing your own rainwater collection system.
Finally, we would like to help steer you in the right direction to look into your own personal water tank. After reviewing all of the information in this guide, we hope that you now have a pretty good idea of what kind of water tank you want and what you are going to use it for.
Adhering to local regulations and cashing in on available rebates will help you get the most out of your water tank, while avoiding any potential headaches.
Regulations for water tanks are strictly enforced, especially in areas with a high population density. Although specific regulations can boil down to individual neighborhoods, water tank regulations are generally governed by state authorities.
For example, here is the development for water tanks in NSW. Conversely, you can see that the regulations in Victoria are much different. Always check your state’s regulations before purchasing a rainwater storage tank.
Lastly, your water tank may be able to qualify for a government rebate. For the most up to date information about Australia’s water tank rebates, you can visit: https://www.energy.gov.au/rebates/rainwater-tank-rebate.
Currently, the government is offering a few different tiered rebates depending on the size and nature of your water tank. There are many terms that apply and rebates are not available in all areas of the country.
Water Tank Manufacturers
Water tanks come in a variety of shapes, a wide range of colours, and a bewildering assortment of brand names. There are more brands of water tanks than you can poke a stick at, including:
- Nylex Plastank
- Clark Tanks
- Team Poly
- Precison Poly
- Poly Water Tanks (the former ARI Plastank)
- and a host of others around the country
Since 1997, Clark Tanks have been making superior-quality poly water tanks. Starting with just one factory in Dalby, Queensland, Clark Tanks have grown into Australia’s largest poly water tank company.
Today, Clark Tanks have five factories- at Dalby and Brisbane in Queensland, Bathurst in NSW. and Moama and Melbourne in Victoria. Their sister company, Tanks Direct, services Northern and Central Queensland.
Clark Tanks offer high-quality, top features and excellent pricing.
Nylex Water Tanks
Nylex has been an iconic Australian brand for generations, and recent years have seen them expanding their operations in the water tank field.
Starting with the purchase of the ARI Plastank business at Pakenham, near Melbourne, they now also have factories in Sydney, Brisbane and Bundaberg. Nylex water tanks are some of the best tanks in Australia. Nylex water tanks are available to customers in Victorai, NSW, ACT and Queensland.
In particular, the Nylex DownUnda underground water tank is a game changer.
The new breed of water tanks can not only save gardens, they can harvest rainwater and directly feed toilets, washing machines, even whole houses, using products such as the Onga WaterSwitch.
Team Poly Water Tanks
Another iconic Australian company is Hills Industries, now making it’s mark in the water and energy-saving field.
Taking over one of the largest water tank businesses in Australia, Team Poly Water Tanks, has helped propel Hills past the magic A$1 billion turnover mark.
You’ll immediately notice that Team Poly water tanks use the traditional corrugated-iron-style profile.
Poly Water Tanks
Not all tank manufacturers are $billion companies. Sometimes there are brilliant designs, high quality manufacture and extra geograhical spread from other manufacturers, like Poly Water Tanks.
With a unique range of round and slimline tanks from 700 to 5000 litres, you can purchase Poly Water Tanks in the Brisbane, Sydney, Canberra, Melbourne and Adelaide Regions.
As the business of water tanks in Australia has moved from just rural, to strongly urban, a new breed of water tank has emerged for space-challenge urban cutomers- the slimline water tank.
Precision Poly saw the need for slimline tanks, and developed an innovative range of good-looking slimline tanks, from 1100 to 3000 litres.
Customers now enjoy the Precision Poly slimline style in the Brisbane, Sydney, Canberra and Melbourne regions.
Tankmasta Water Tanks
A new breed of underground water tanks has developed, such as Tankmasta, and become common in new home construction. Featuring rugged, shallow design, they are the “best water tanks you’ll never see.”!