Quality of any water is determined by the quantity of source water, its exposure to contaminants during collection, treatment and storage. In a roof top rainwater harvesting system, which consists of a collection system, a conveyance system and a storage system, contamination of water can occur at any of these stages.
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/health-aspect-rain-water-harvesting
[2] http://admin.indiaenvironmentportal.org.in/category/author/roy-m-thomas
[3] http://admin.indiaenvironmentportal.org.in/category/author/benny-mathews-abraham
[4] http://admin.indiaenvironmentportal.org.in/category/journal/journal-institution-public-health-engineers
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-treatment-technology
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-harvesting
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-quality
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/rainfall