Factors Influencing the Bacteriological Quality of Spa-Pool Waters in New South Wales (Australia)

Abstract

The increasing popularity in the use of spa pools during the 1970's and 1980's and the accompanying incidents of folliculitis and ear infections caused by Pseudomonas aeruginosa associated with spa-pool use has necessitated the development of bacteriological and chemical guidelines for spa-pool water quality. The New South Wales (N.S.W.) Department of Health introduced a bacteriological standard for swimming pools and spa-pools in 1981 based on the findings of a series of surveys aimed at identifying the principal factors influencing the bacteriological quality of spa waters. Four surveys are summarised in this paper. The major findings described are the tenfold higher recovery of P. aeruginosa from spa-pools than from outdoor pools; the need for at least 2.0 milligrams per litre (mg/L) free chlorine residual in order to achieve reliable satisfactory water quality in spas compared with a requirement of 1.0mg/L to achieve the same quality in outdoor pools; the need to maintain pH below 8.0 in order to ensure efficient chlorine disinfection; the apparent inability of bromochlorodimethylhydantoin to adequately disinfect spas during heavy bather load periods; and the success of the Health Department's spa-pool operator education program which resulted in a 30% reduction in the incidence of bacteriologically unsatisfactory spa-pool waters in N.S.W. between 1980 and 1986.