Is
your collection roof area big enough to fill your
tank in an average rain?
1.
First, decide what you will be using rainwater for
in your circumstances.
2.
Using
the following table, determine the total rainwater
you use per day - this is your "Required
Daily Yield." You can use this info
for the "Is my tank capacity big enough?"calculator.
USE
(Appliance)
TYPE
AVERAGE
RATE OF FLOW
AVERAGE
TOTAL WATER USED
Shower
(average shower is 8 min)
Normal
Shower Rose
15
litres per minute
120
litres per shower
Water
Saver Rose
8.5
litres per minute
68
litres per shower
Toilet
Single Flush
12
litres
120
litres per day
Dual
Flush
6/3 litres
40
litres per day
Washing
Machine
Twin
Tub
40
litres per wash
Front
Loading
80
litres per wash
Top
Loading
170
litres per wash
Dishwasher
20-50
litres per load
Cooking,
Cleaning & Drinking
10
litres per minute
150
litres per 24 hour day
Brushing
teeth with running water
5
litres per brush
Bath
10-20
litres per minute
50-150
litres per bath
OUTDOORS
Sprinkler
or Handheld Hose
10-20
litres per minute
1000
litres per hour
Drip
System
4
litres per hour
Hosing
Paths/Driveways
20
litres per minute
200
litres for 10 min
Washing
the car with a running hose
10-20
litres per minute
100-300
litres
Filling
a swimming pool
Up
to 55,000 litres
This
information is provide courtesy of Brisbane Water, Brisbane
City Council, and is intended as a guide only.
The
"What size tank do I need?"
Calculator
To calculate the tank size best suited to your rainwater
needs, you'll need to know if the tank is big enough
to get you through the dry season.
Follow
these 4 steps to work out your ideal tank size:
1.
With the help of the table above, determine what
you will be using your rainwater for. This will
depend on your personal choice, as well as plumbing
and other circumstances.
2.
Add
up the litres of rainwater you think you will
be using over an average day, (don't forget to
include an average of those once-a-week situations
like washing the car or topping up the pool).
This
is your "Required Daily Yield"
of rainwater.
3.
From
your experience, determine how long your dry season
can last.
"In
my experience, Brissy has gone 3-4 months without
"rain" - and it's the dry time I really
have to plan for..."
4.
In
the calculator below, select your "period between
significant rainfall" and type in your "Required
daily yield". This will give you an estimate
of your ideal tank size.
The
"How much water did I just collect?"
Calculator
Is your
collection roof area big enough to fill your tank in
an average rain?
1.
What is the roof area (width x length) that goes
into the downpipe(s) connected to the tank?
2.
What
is the rainfall in the last rain (in millimetres)?
(N.B.:
the following rainfall map is a guide only and
is the total rainfall for the whole year - click
through to the Bureau of Meteorology for current
rainfall: www.bom.gov.au
The
"How much water does my current
tank hold?" Calculator
Use this
calculator to estimate the volume of your cylindrical
tank. Please enter the diameter
and the height of your tank below.
