Guide to selecting a Rainwater tank

Rainwater Harvesting

10mm of rain on a roof area of 100 square metres
will give you a possible 1000 litres of rainwater into your tank

Use the following table to help select the right rainwater tank

Annual rainfall
Roof area in m2	250mm	500mm	750mm	1000mm
36	9000 L	18000L	27000L	36000L
50	12500 L	25000 L	37500L	50000L
100	25000 L	50000 L	75000L	100000L
200	50000 L	100000 L	150000L	200000L
300	75000 L	150000 L	225000L	300000L
400	100000 L	200000 L	300000L	400000L
500	125000 L	250000 L	375000L	500000L

Indoor
water
usage

Number of
people
in house

Volume
of
water
used

no
of days

Volume of
water
required

Indoor water usage

	1	2	4
shower, bath, toilet, basin	250L	500L	1000L	x	365	=
Washing machine	120L	130L	150L	x		=
Dishwasher	35L	35L	35L	x		=

Outdoor water usage

Garden
size

garden
only

garden
& lawn

Volume
of
water
used

no
of
days

Volume
of water
required

Average daily useage outdoors

Small	150L	370L	x	365	=
Medium	165L	520L	x		=
Large	180L	1140L	x		=


Total water require Indoor + Outdoor =