Resources
Rain Water
Tanks - Sizes and Types
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 reliable and effective it is in
conserving water or managing stormwater. As a guide, we recommend:
-
A minimum size of 5,000 litres for non potable (non drinking) domestic water uses
(e.g. flushing the toilet, in washing machines, watering the garden, washing the
car) and holding stormwater
- A minimum size of 2,000 litres for toilet flushing
use only or when you have a small garden area to water.
Things
to consider
- The number of people living in your home (if you
want to use rainwater for toilet flushing).
- The amount of water you
currently use.
- The size of your garden.
- Intended use of
rainwater (e.g. garden, toilet flushing).
- Available fittings and components
to suit your needs.
- The size of the roof catchment area.
- The location of the property (coastal areas are generally wetter than inland
areas so a larger tank is required inland to be as effective as a tank on the
coast).
- Local council requirements.
Types
Polyethylene tanks
Commonly known as 'poly' tanks, these tanks come in many sizes and colours and
are suitable for both above and below ground use. They last a long time, are UV-resistant,
cost less than metal tanks and, because of their lightweight construction, are
easy to transport.
Metal tanks
Metal tanks are light and easy to transport, are suitable for above or below
ground use, can be custom made and are usually corrugated or straight rolled.
They can be made from a variety of metals including:
- Galvanised steel -
zinc-coated Z600 steel (prone to rusting)
- Aquaplate or Colorbond - coloured
polymer-coated steel (lasts longest)
- Zincalume - silver-coloured zinc/aluminium-coated
steel (prone to rusting)
- Copper and stainless steel - used for specialised
applications.
- Concrete
Concrete tanks can be built above or below
ground. They're usually made on site and are durable and long lasting. However,
they can sometimes crack - especially when 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 rainwater tanks are resistant to rust and chemical corrosion and
are suitable for both ground and stand installations. They are tolerant of extreme
temperatures, come in a large range of colours and sizes and, because of their
lightweight construction, are easy to transport. Fibreglass tanks can be more
expensive than other varieties. 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 children,
adults and animals drowning or contaminating the water
- Can be damaged by
heavy vehicles driving over them
- Excavation costs.
Sourced
from the Sydney Water website
Sydney Water -www.sydneywater.com.au
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