Microbiological quality of the water of recreational and rehabilitation pools: a 2-year survey in Naples, Italy

Summary Objectives To analyse and compare the microbiological quality of the water in rehabilitation and recreational swimming pools in Naples, Italy. Study design A 2-year survey investigated the microbiological quality of the water in seven recreational and rehabilitation pools, and the findings were compared with local guidelines. Methods For each facility, water was sampled at the intake point and at two points inside the pool. Total microbial contamination and Pseudomonas aeruginosa contamination were evaluated. Results Microbial mesophilic contamination and P. aeruginosa contamination were found in all seven pools. Microbial mesophilic contamination was more common in recreational pools (3–4.2% samples were above threshold values), probably due to the greater number of bathers. P. aeruginosa was more common in intake water than water inside the pool [mean values of 19.3 and 22.5 colony-forming units (cfu)/ml in recreational and rehabilitation pools, respectively]. A longer period of contact with chlorine and the dilution process may have led to lower levels of P. aeruginosa in the pool water (range 2–15 cfu/ml). Conclusions There is a need to improve disinfection and cleaning procedures, with consideration given to the different uses and daily bather loads of each pool type. There is also a need to monitor water quality and to increase users' knowledge and awareness of the risks.