A chara, – We need to provide adequate security of water supply in this country, as Danny O’Connor writes (August 2nd).
Much work is required. Why, however, do we neglect a significant supply already here? According to Met Éireann, the average rainfall in the Dublin area is about 732mm.
This means that on the roof of a modest home with a ground area of 6.5 x 7.5 metres, on average over 35,000 litres of rain fall annually.
Even in the driest month of July we have an average of 50mm, yielding about 240 litres.
Not all of this 35,000 litres could be used, of course, and falls are not equally spread over the year, but it could make a significant contribution.
There seems to be no move to harvest rain for uses which do not require treated water. It is not covered by grants for environmental improvements of homes. Flushing of toilets is estimated to use 25 per cent to 30 per cent of current treated supply.
Next year we will have a household tax of €100.
Our Government could use this imaginatively by giving a grant of €100 for domestic rainwater harvesting for household (not garden) use.
In case of breakdowns in the treated water supply, the home would still have its own reservoir for some uses.
This would reduce the demand on emergency tankers. In normal times, it would help reduce liability to water charges when introduced.
As we move from the present 34 local authorities to a single water authority, the harvesting of rainwater would spread our reliance over many sources and make the supply more secure. – Is mise,
PÁDRAIG McCARTHY, Blackthorn Court, Sandyford, Dublin 16.