 Rainwater
harvesting constitutes capturing rainwater runoff from a collection
surface and storing it for later use. In principal rain can
be harvested from any source but the most attractive option
is a relatively clean surface such as a roof top.
Water Quality:
Rainwater quality reflects ambient air quality and the cleanliness
of the collection surface but in general it is ‘soft’,
clean and contains far fewer dissolved minerals than other
sources. The degree of further treatment required is dependant
upon the intended use. In most cases water for ‘grey
water’ type applications (Toilet flushing, laundry,
garden irrigation etc.) requires only primary screening to
remove leaves and large sediment particles. Water for more
demanding applications, such as bathing, is generally filtered
further and sterilised with Ultra Violet light.
Typical Domestic Water Usage Patterns:
The average Irish household uses 150 litres of water per
person per day, only 75 litres (50%) of which is required
to be sterile. The remainder is ‘grey water’ type
usage for which unsterilised water is adequate. These figures
can be improved upon and with a little care and some simple
water conservation techniques it is often possible to reduce
daily consumption to between 100 – 120 litres / person.
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