3rd International Rainwater Cistern Systems Conference
Khon Kaen, Thailand - January, 1987

Section F: Water Quality

Paper F.3

The Microbiological Quality of Cistern Waters in the Tantalus Area of Honolulu, Hawaii

Roger S. Fujioka
Researcher
Water Resources Research Centre and School of Public Heath
University of Hawaii
Honolulu
Hawaii 96822
USA

Robert D. Chin
Graduate Student
School of Public Heath
University of Hawaii
Honolulu
Hawaii 96822
USA

The drinking water quality of cistern waters in the Tantalus area of Honolulu, Hawaii was evaluated by analyzing 18 cistern systems for concentrations of bacteria, conductivity/ turbidity and total solids. The results indicate that concentrations of total salts, and total solids in these cistern waters were well within the current U.S. drinking water standards. Moreover, only 2 of 36 cistern water samples exceeded the maximum turbidity level of 5.0 NTU established for individual sources. However, high concentrations of one of the three fecal indicator bacteria (total coli-form, fecal coliform, fecal streptococci) were often recovered from these waters indicating that most of the cistern waters would not be able to meet U.S. microbiological drinking water standards. Fecal streptococci was recovered much more frequently and at higher concentrations than coliforms indicating that the source of fecal contamination was birds rather than humans. These cistern waters were also determined to contain very high concentrations of total bacteria, almost always exceeding 500/ml, the minimum level at which interference with the recovery of total coliform bacteria have been reported. Since assays for fecal coliform and fecal streptococci are not interfered by the presence of high concentrations of total bacteria, we recommend that these alternative indicator bacteria be analyzed for to determine the extent of fecal contamination of cistern water supplies.

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