Reports

Report Number: 45
Year: 1983
 

An Investigation of Water Quality of Rooftop Rainwater Catchment Systems in Micronesia

This research involved an investigation of rainwater catchment system (RWCS) characteristics and water quality in Micronesia. The objectives of the research were to determine the bacteriological state of existing RWCS waters by analyses of fecal and total coliform bacteria and to try and identify those catchment characteristics and maintenance practices which affect catchment water quality.

A total of 203 different RWCS were sampled in Kosrae, Ponape, Yap and Palau. Seventy-one percent of the RWCS sampled had no fecal coliforms per 100 mL, and 37 percent had no total coliforms per 200 mL. Eighty-five and 70 percent had 5 or less fecal and total coliforms respectively per 100 mL. Cleaning the catchment tank, roof and gutters were not found to affect RWCS water quality significantly. Total coliform counts were significantly affected by screening the tank inlet and by the type of catchment tank.

In general, screens and tank coverings improved water quality. The newer ferro-cement tanks had the best water quality, while metal barrels had the poorest.

Catchment tanks were the largest and most popular source of water in Yap, where water is less plentiful. Catchment tanks were also popular in areas with other sources of water. Even in areas with treated piped public water supplies, catchment systems appeared to be preferred for drinking purposes because of objections to chlorine taste and mistrust of the quality of public water.

Author(s):
Theo A. Dillaha
William J. Zolan