When choosing a rainwater tank in Brisbane, there are many things to consider. With such a wide range of options on the market, it can be hard to know where to start. This buyer’s guide will help you choose the right rainwater tank for your home or business.

How Do Rainwater Tanks Work

Collecting rainwater is an ancient method that has been practiced by mankind for centuries. Eventually, rainwater tanks were then invented, helping us to be more efficient in this process. Here’s how a typical rainwater tank works:

1. When it rains, the water that falls on the roof will be collected in a catchment area.
2. The water is then funneled into the gutters. 
3. From the gutters, the water flows through the downpipes and filters. 
4. The rainwater finally ends up in a tank, where it will be stored.
5. If the tank has a pump, the pump will pull the water out from the cistern through a small pipe when the water is used. 
6. Depending on how the water from the tank will be used, some homeowners put an additional filter before the water from the tank passes through.
7. Depending on the layout of the water storage system, the rainwater will then come out through the faucet that’s connected to the tank or to other fixtures inside the house or building.
8. Should the tanks fill up, there’s an outlet pipe that will drain out the excess water into the waterways. 

Different Rainwater Tank Dimensions and Capacities

As previously discussed, the right size of tank for your household will depend on the rainwater storage capacity needed. Here are the different dimensions and the corresponding capacities for both the slimline and round water tanks.

1. Slimline Water Tank Dimensions & Capacities

2. Round Water Tank Dimensions & Capacities

How to Determine the Right Size of Water Tank for Your Home

There is a basic formula to calculate the best size of rainwater tank for any home or building. In this formula, you will use the supply of water from your roof to find out the most appropriate size tank for you. The formula is as follows:

footprint of the property (m²) x drainage coefficient x filter efficiency x annual rainfall x 0.05 = recommended tank size

Where,

Footprint of the property = the length times the width of the building in meters. 

Drainage coefficient = 0.8, where it is a constant number accounting for the rainwater loss and suggests that 80% of the rainwater that hits the roof will go to the tank as some will evaporate and some will splash over the gutters in a heavy downpour.

Filter efficiency = 0.95, where it is a constant number and implies that only 95% of all rainwater will get through the filter, as some will be lost due to some factors such as the filter’s self-cleaning process.

Annual rainfall = the amount of precipitation in mm for a certain location in a year. You can simply search online to find out the annual rainfall in Brisbane.

Multiplying all of the above variables will give us the amount of water that you will receive in the tank in one year. We will then multiply that result by 0.05, which is 5% of a year’s water, and the result gives us our final tank volume.

Example:

Roof area = 100m²

Drainage coefficient = 0.8

Filter efficiency = 0.95

Brisbane’s annual rainfall = 1200mm

To calculate,

100 x 0.8 x 0.95 x 1200 = 91,200 liters of water received in a year

Then, multiply that with the constant 0.05,

91,200 x 0.05 = 4,560L

The result shows that approximately a 4500L tank suits this particular household or building.

Price Range of Rainwater Tanks

Rainwater tanks come in numerous sizes and shapes with different specifications for various purposes. If you’re planning to buy a rainwater tank, you may wonder how much it will cost. Here are the price ranges of the different categories of water tanks.

However, the price of a rainwater tank is affected by a number of factors such as the following:

• Size of the tank
• Type of material the raintank made of
• Location of the tank supplier

Cost of Installing a Rainwater Tank in Brisbane 

Rainwater tank installation in Brisbane can range from $350 for a simple install to $1200 or more for an integrated system. On a per-hour basis, plumbers may charge around $77.50 per hour to $88 per hour.

Various factors can also affect the installation cost such as the following:

• Size of the tank
• Type of material
• Ease of access
• The difficulty of installation

To know the exact cost of rainwater tank installation, talk to a professional service provider and discuss your options. In most cases, water tank suppliers also offer installation services for these water storage systems.

How to Install a Rainwater Tank

Once you have purchased your water tank, you may be considering a DIY installation in order to save costs from hiring a professional plumber. While each rainwater tank may slightly differ in installation, the following steps can be applied to most tanks.

1. Select a Suitable Location for the Tank

First, it is important to choose a suitable location for your tank. Take note that the tank will be connected to any roof gutter the rainwater will be collected from. Hence, it should be located nearer to a downpipe.

2. Prepare the Base

Some options for the base are concrete, a bed of sand, and a platform made from timber or steel. But remember that water tanks can be heavy when full and thus, a strong and sturdy base is recommended. 

Usually, the tank supplier will indicate the minimum requirements for the base when you purchase it. They may advise a platform base with a specific height to gain pressure at the hose nozzle. Generally, concrete and platform bases are better long-term options.

For this step, you may need to hire professional services to do the carpentry and if any, metal welding works for the base. However, you can still DIY it if you think you can handle such tasks, especially if it just requires a simple concrete base.

3. Get the Tank into Position

When the base is ready, the next step is to get the tank into position. While some tanks are not that heavy, most are certainly big, and hence, you will need help from another person to lift the tank into its newly-prepared base.

4. Connect the Downpipe from the Gutter to the Tank

Now, decide which downpipe from the gutter will be connected to your tank. Disconnect that downpipe first. You may use an elbow connector, downpipe adapter, and another pipe with an appropriate length to connect it to the inlet of your rainwater tank.

It is recommended to clean the gutter first before connecting the downpipe to the tank. In this way, you can avoid anything that could potentially contaminate your tank water.

5. Install Pre-Tank Filter (Optional)

If you will use the collected rainwater for human consumption, talk to your dealer about what filters you will need. You might need a pre-tank filter in order to separate dirt particles and debris before the rainwater goes into the tank.

These are rainwater strainers and filters that can be installed from your rooftop, on your gutters, along your piping, or into your tank inlet. Nowadays, there are available rainwater filters with stainless steel inserts, allowing for easy cleaning and maintenance.

6. Attach the Overflow Outlet

A water tank overflow serves as an exit path for the excess incoming water. It also helps remove the floating particles on the surface of the water inside the tank.

Many rainwater tanks today have already pre-installed overflow fittings. You just need to connect a pipe from the tank overflow outlet going into the stormwater drainage where the old downpipe used to be connected.

7. Connect the Outlet Fittings to the Tank

Most water tanks today have already threaded outlets in place of at least, usually two. The outlet is where the water leaves the tank before going to the point of use. Mostly, outlets are located at the bottom as water is drained from the bottom of the tank.

The ball valve and tap fittings are also supplied when you purchase your tank. Here, you just have to match the threads to install them. You may apply some thread tape to the fittings before carefully screwing them into the outlets to ensure a good seal.

8. Connect the Pump (Optional)

In many cases, a pump is needed to get the water out of the tank. The best location for the pump is to put it as close as possible to the water tank and on the same level as the base.

A pump is usually connected to a rainwater tank with the use of a non-return valve and a small-length suction hose. While water tank pumps are designed to endure various weather conditions, it is still a good idea to keep them covered for more protection.

9. Install the Rainwater Tank Gauge (Optional)

The rainwater gauge will help you determine the level of water inside the tank at a glance. Mostly, such devices are simple and easy to install. They are also compatible with the existing and new tanks.

10. Place the Sediment Filter

A sediment filter is used to remove the fine particles that may remain in the rainwater tank after pre-filtration. As the rainwater is now ready to run from the pump to the point of use, the sediment filter is recommended to be put on the pressure side of the pump.

Basically, the sediment filter is placed near the point the water service line enters the house or building. In this way, it will prevent unwanted particles from reaching downstream appliances and other fixtures, which can eventually damage them.

11. Other Additional Work

In order to power up the pump, you may need to install a new power point next to the pump if none exists. Hiring a licensed electrician may be needed for this task. Finally, test your pump by plugging it in and see if it turns on well.

Now, you have a fully operational tank that is ready to collect rainwater. When the rain comes and the tank is filled with water, check if everything works well as expected and see if there are some leaks on the outlets.

Different Material Types of Rainwater Tanks

There are four main material types from which a rainwater tank can be made of: polyethylene (plastic), steel, fiberglass, and concrete. Each of these materials has pros and cons and thus, you need to weigh the costs and benefits of each.

1. Polyethylene

Polyethylene or also known as poly tank is definitely the most common material type used in rainwater tanks, especially in residential properties. It is basically a plastic material that is known for being resilient and lightweight.

Among the advantages of this type of material are its lower cost and non-corrosive property. It also comes in many sizes and colors. Today, many poly water tanks comply with the light transmission standard that prevents the growth of algae.

2. Steel

Steel rainwater tanks are the traditional type that have been used for ages. There are many advantages to this type of material such as fire-resistant, termite-proof, and durability. But there are a few variations of steel tanks such as the following.

1. Steel Liner Tanks

Steel liner tanks are tanks made of steel but they have a poly liner that prevents the water from coming into contact with the galvanized walls. With this, the problem of corrosion is avoided and as the poly liner holds the water, it is ideal for storing potable water.

2. Galvanized Steel Water Tanks

Before, most water tanks were made from galvanized steel as can be seen in older buildings and houses. The downside with this type of material is it is prone to corrosion and thus, the lifespan of the tank is relatively short.

3. Stainless Steel Tanks

This variation of steel used in manufacturing water tanks doesn’t have the rust or corrosion problems that are common among types of steel. However, stainless steel can significantly cost more compared to normal coated steel and plastic tanks.

3. Fiberglass

The main advantage of fiberglass tanks is their rust and chemical-resistant properties. Although this can be an expensive option, it is rigid and able to withstand extreme temperatures. This type of material can also be installed above or below ground.

4. Concrete

Concrete tanks are durable, strong, and have the best bushfire resistance. Here, you have the option for a prefabricated one or it can be constructed on site to meet the specific demands of the homeowner.

Benefits of Having a Rainwater Tank

In recent years, many households are into rainwater harvesting systems with the use of rainwater tanks. It’s no wonder why, as this method of storing water has a lot of benefits such as the following.

1. Save Money on Water Bills

With a rainwater tank, you will not solely rely on your main water supply for your household’s water needs. Although you will initially invest in the installation of this water storage system, it will save you money on your monthly water bills in the long run.

2. Backup Water Supply

In times of drought or water restrictions, your rainwater tank can be readily your source of water supply. Depending on the type of filtering you install, this can also be your source of drinking water.

3. Eligible for Government Rebates

In Brisbane, those households with rainwater tanks, pumps, and diverters may be eligible for a $1000 rebate. If you have 3000 plus-liter tank storage that is connected to a laundry cold water tap or toilet suite, you may qualify for a rebate of up to $1500.

4. Environment-Friendly

As more and more households are adopting a rainwater storage system, it lessens the strain on waterways which will result in lesser local flooding. As it also decreases the amount of heavy stormwater runoff, it implies less damage to bodies of water.

Where to Buy Water Tanks in Brisbane

Here are some water tank suppliers in Brisbane. Just contact each of them for more information.

1. Bunnings Newstead

In Australia, Bunnings is regarded as the top supplier of home improvement and lifestyle products. They have an extensive range of water tanks to choose from at bargain prices.

2. The Tank Factory

The Tank Factory is one of Australia’s top water tank manufacturers. They have a wide selection of high-quality tanks to choose from, whether you need a 340-liter tank, a 34,000-liter tank, or something in between.

3. QTank

QTanks’ products are triple-tested and constructed using the best materials available. Their tanks are certified to the Australian Tank Standard AS4766. Moreover, they provide a 10-year warranty on their products against manufacturing defects.

4. Tankworld

Since its founding in 1972, Tankworld has grown to become one of the most reputable and successful names in the water tank industry. It is 100% Australian owned and all their products are made in Australia.

5. Kingspan Water Tanks

Kingspan Water Tanks was established in 1934 and today, they have local manufacturing facilities in Sydney, Brisbane, Perth, and Melbourne. Due to their quality management system, their products are guaranteed to last.

When buying a rainwater tank in Brisbane, you have to take into account a number of factors before narrowing down your options. The above-mentioned points will guide you to get the best water tank solution for your rain collection system.