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Sizes and Types of Rainwater Tanks
- Rainwater tank rebate program
- How rainwater tanks work
- Planning for a tank
- Sizes and types of rainwater tanks
- Installing a rainwater tank
- Tips for maximising water savings
- Maintaining a rainwater tank
- Water quality
Sizes
It's important to make sure you get the right size rainwater tank to suit your needs. Generally, the larger the tank, the more water can be saved. We recommend a minimum tank size of:
- 5,000 litres for all non drinking household use such as flushing toilets, washing clothes, watering gardens and washing cars
- 2,000 litres for some household use such as toilet flushing and watering a small garden area.
You should also consider:
- how many people live in your home - an average four-person household uses about 7,000 litres of water each week
- the size of the roof catchment area the tank is connected to, as this will limit the amount of water you can collect.
Types
Tanks can be above or below ground, come in a variety of materials and cater to a range of budgets. You can speak to your tank supplier about the advantages and disadvantages of different tank types before choosing one that's right for you.
Polyethylene tanks
Commonly known as 'poly' tanks, these tanks are durable, UV - resistant, light and easy to transport. They are available in many sizes and colours and can be placed above or below ground.
Metal tanks
Metal tanks are light and easy to transport, can be custom made and are suitable above or below ground. They are usually corrugated or steel coated.
Concrete
Concrete tanks can be built above or below ground. They're usually made on site and are durable and long lasting. They can crack, especially if they are below ground in clay soil. They're good for preventing algal growth (light can't penetrate) and they keep water cool.
Fibreglass tanks
Fibreglass tanks are lightweight, tolerant of extreme temperatures and are resistant to rust and chemical corrosion. They are easy to transport and come in a large range of colours and sizes. They are best placed above ground.
Above ground tanks or below ground tanks?
Above ground tanks
Advantages:
- easy to detect cracks and leaks
- can extract water via gravity and/or pumps
- can be raised off ground to increase water pressure
- easy to drain for cleaning
- usually cost less than below ground tanks.
Disadvantages:
- take up space
- susceptible to weather
- require anchoring (to the ground) for when the tank has less water.
Below ground tanks
Advantages:
- save space and are unobtrusive
Disadvantages:
- more difficult to extract water from - usually need a pump
- hard to detect leaks or problems
- hard to empty when top is left on - difficult to drain for cleaning
- risk of contamination from groundwater or floodwaters
- can be damaged by tree roots
- if access point is left uncovered, there's a risk of people and animals drowning or contaminating the water
- can be damaged by heavy vehicles driving over them
- excavation costs.