It is important to be aware that the water quality in tanks can be affected by many things, such as:

• Atmospheric pollution
• Bird and possum droppings
• Roofing materials and paints
• Trapped insects and small animals
• Rotten leaves
• Dust on rooves
• Installation

There are a variety of accessories, such as Roof Gutter Guards and First Flush Water Diverters, which can help to keep rainwater quality high.

The following simple rainwater tank installation and maintenance practices will ensure the best possible water quality:

• Clean inlet strainers whenever necessary
• Make sure the inlet strainers, mosquito proofing and lids are in good repair. Lids should be tight fitting. Screens should be compliant with Queensland Health regulations.
• Keep gutters and roof clear of leaves and other material. More frequent checks are needed if there are overhanging trees. Gutter mesh may be installed.
• It is a good idea to have a “first flush” diverter. This diverts the first wash of dusty roof water away from the tank and helps reduce sediment.
• Filtering of the rainwater is a good idea and helps reduce sediment.
• It is important to minimise light entering the tank to inhibit algae growth.
• Check for sludge every few years. Tanks need to be drained and cleaned every few years to remove the mud, which comes from dust settling on the tank floor.

Choosing a Rainwater Tank

Once you’ve decided to get a rainwater tank, the size of the tank you will need depends on:

• Rainfall in your area
• Roof area available
• The number of people living in the house
• How much rainwater you will use per day

For a guide to the average amount of rainwater you will use per day, apply the following information to the areas you plan to use rainwater.

Average Domestic Water Usage

The figures below on domestic water usage could vary depending on personal habits and design of household appliances. However, Brisbane City Council estimates that 1,100 Litres are used per day by an average Brisbane family (2 adults, 2 children).

* Average of 5 times per day for 3 minutes per use at a flow rate of 10 litres per minute.
For further information, please contact the Brisbane City Council Call Centre on 3403 8888.

This information is provided courtesy of Brisbane Water, Brisbane City Council, and is intended as a guide only.

To calculate the approximate water tank size you need:

1. On the Average Annual Rainfall Map, determine your annual rainfall – high/medium/low.
2. Determine the size of your roof or catchment area – one downpipe/small roof/medium roof/large roof.
3. From the Average Domestic Water Usage tables in section 4 (above), calculate the average litres of rainwater your household will require per day – your required yield.
4. On the table, you will find a range of different yields, depending on the tank size. Determine from the table the tank size (kilolitres) you will require.

For more information on WaterWise, phone your local Council Water Board or the Department of Primary Industries.

This information has been provided courtesy of WaterWise and the Department of Primary Industries and is intended as a guide only.

There are many different types of tanks, all with their own advantages and disadvantages. For a general description of rainwater tanks, following is an extract from the report WaterWise in the Home – FH6 published by the Queensland Department of Primary Industries and WaterWise Queensland*:

Galvanised Tanks

“The most common type of tanks is the galvanised variety, which is available in rust-resistant linings, such as Zincalume or Aquaplate. It is the most inexpensive but has a limited life span.

“To reduce corrosion in these tanks, a dispenser of crystals of metaphosphates is sometimes used prior to initial filling.

“New galvanised tanks are now available with food-grade polymer lining to help prevent corrosion. When cleaning older tanks, it is important not to disturb the film which builds up in the inside walls of the tank, as this helps protect against corrosion.”

Fibreglass Tanks

“Fibreglass tanks, although more expensive, are longer lasting because they resist corrosion and are not generally affected by chemicals or moisture.

“Fibreglass tanks allow more light entry than other types of tanks, which encourages algal growth. To prevent this, tanks should be sealed with a black covering inside or painted on the outside. Some tanks are manufactured with sufficient pigment to prevent this problem occurring.”

Fibreglass can tend to be brittle in nature, being prone to cracking and leaking.

Concrete Tanks

“Concrete and ferro-concrete tanks are strong and long lasting and can be installed underground. Larger tanks often have to be cast in-situ.

“New concrete and ferro-concrete tanks will need to be adequately flushed to remove the concrete taste from the water.”

Concrete is generally porous and tends to crack, thereby occasionally leaking and allowing tree roots to enter.

Polyethylene Tanks

Polyethylene tanks do not corrode, are relocatable, are made from a very strong material and are generally the longest lasting tanks.

Generally, high quality polyethylene materials are used, which don’t give out any taste or smell. UV-stabilised, food-grade polyethylene is generally an industry-standard.

Provided that the tanks are made at the correct thickness, algae growth does not occur.

Most of the larger size tanks have leaded PVC support poles to hold up the roof. Poles may wear holes through the roof and they take a lot of effort to stand up if they fall over and the roof collapses.

Polyethylene tanks are rotomoulded. Some tanks are made with a vertical seam and this, being a weak point in the tank, may cause splitting and water loss.

With such a large variety of tanks to choose from, it can be a challenge to find the best tank for you…

Gough tanks have all the advantages of polyethylene tanks:

• Relocatable
• No rust or corrosion
• No taste
• No smell
• No algae
• No brittle or porous materials
• UV-stabilised
• Food-grade polymers
• Long-lasting

So What’s the Difference?

The difference is that GOUGH TANKS have the following important, unique features, solving the disadvantages:

• An easy-access manhole
• Mozzie-proof mesh on strainer and overflow – Queensland Health compliant
• Thick walls
• Top-quality fittings
• Pure Cotene¨™ materials – only the best!
• No PVC support poles

The Tankulator is a free online tool which calculates what size rainwater tank best suits your needs – tankulator.ata.org.au.