John Gould
ASAL Consultants / Lincoln University
107, Studholme St., Christchurch, New Zealand
E-mail: john.gould@xtra.co.nz

Numerous studies have shown that due to contamination following contact with the catchment surface, stored rainwater often does not meet WHO guideline standards for drinking water especially with respect to microbiological quality criteria. This does not in itself mean that rainwater is unsafe to drink. Millions of people in rural areas around the world depend on rainwater for drinking and other domestic purposes and the number of reported cases of serious health problems related to rainwater supplies are very few. In this paper, some of these rare rainwater related disease outbreaks and other potential health risks due to atmospheric pollution contaminating rainfall are reviewed. Other concerns resulting from heavy metal and chemical contamination are also examined and findings from surveys conducted in North America, Australasia and Asia are discussed. While health risks may be small, these findings suggest there is little room for complacency and every effort needs to be taken to minimize rainwater contamination. Several methods to improve the quality of water produced by any rainwater catchment system are briefly described including appropriate system design, sound operation and maintenance, first flush devices and treatment.