- Rainwater tanks and microbial water quality: are the indications clear?
- Evans, C.; Coombes, P.; Dunstan, H.; Harrison, T.; Martin, A.; Morrow, A.
- Australian Journal of Water Resources Vol. 12, Issue 2, p. 143-152
- Engineers Australia
- Resource Type
- journal article
- Deriving maximum economic and water savings benefits from rainwater harvesting in the urban environment requires the use of rainwater for internal applications, including showering/bathing, laundry and toilet flushing. Widespread use of rainwater for these applications has been hindered by uncertainty over quality and perceptions of health risk. This study examined the presence and abundance of the faecal indicators E. coli, enterococci and total coliform in over 100 water samples collected from rainwater tanks in eastern Australia. A large proportion of samples were compliant with the requirements of mains water drinking standards, especially among those collected via a hot water system, while almost universal compliance with bathing water quality standards was observed. Indicator species were found to represent a very small proportion of total bacterial contamination and no significant correlation between faecal indicator counts and heterotrophic plate counts was observed. Furthermore, enterococci were not significantly correlated with the other indicator groups. On average, heterotrophic counts were found to be dominated by Pseudomonas spp and several other widely distributed environmental organisms. The implications of these findings with regard to the scope of domestic rainwater use in the urban environment, and the difficulty in achieving reliable risk assessment, have been discussed.
- water harvesting; rain water; water microbiology; water quality
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