The CDC just reported on the safety of pools in America and it reminded me of the summer of 1998 when 26 children became ill from E. coli O157:H7 contracted while playing in the kiddie pool at White Water Park, a commercial water park in suburban Atlanta. Seven of those children were hospitalized and a 2-year-old girl died from Hemolytic Uremic Syndrome, a kidney disorder caused by E. coli O157:H7.

Operators of the pool initially denied responsibility for the E. coli outbreak, but investigators determined that the chlorine level in the pool was well below the local health standard on the days when the water was contaminated, greatly increasing the risk of infection. The incident increased national awareness of the hazards of water contamination, prompting the industry to pay closer attention to pool cleaning and chlorine.

Read the report:

Swimming is the third most popular U.S. sport or exercise activity, with approximately 314 million visits to recreational water venues, including treated venues (e.g., pools), each year (1). The most frequently reported type of recreational water illness (RWI) outbreak is gastroenteritis, the incidence of which is increasing. During 1997–2006, chlorine- and bromine-susceptible pathogens (e.g., Shigella and norovirus) caused 24 (23%) of 104 treated venue–associated RWI outbreaks of gastroenteritis, indicating lapses in proper operation of pools. Pool inspectors help minimize the risk for RWIs and injuries by enforcing regulations that govern public treated recreational water venues. To assess pool code compliance, CDC analyzed 2008 data from 121,020 routine pool inspections conducted by a convenience sample of 15 state and local agencies. Because pool codes and, therefore, inspection items differed across jurisdictions, reported denominators varied. Of 111,487 inspections, 13,532 (12.1%) resulted in immediate closure because of serious violations (e.g., lack of disinfectant in the water). Of 120,975 inspections, 12,917 (10.7%) identified disinfectant level violations. Although these results likely are not representative of all pools in the United States, they suggest the need for increased public health scrutiny and improved pool operation. The results also demonstrate that pool inspection data can be used as a potential source for surveillance to guide resource allocation and regulatory decision-making. Collecting pool inspection data in a standardized, electronic format can facilitate routine analysis to support efforts to reduce health and safety risks for swimmers.

Prevention of RWIs at treated venues requires pool operators to 1) maintain appropriate disinfectant and pH levels to maximize disinfectant effectiveness and 2) ensure optimal water circulation and filtration. Pool codes, promulgated by individual state or local public health agencies, govern pool operation.

CDC selected a convenience sample of 15 health agencies in four states and 11 counties or cities* to participate in an analysis of pool inspection data. For inclusion, data from inspections had to be in an electronic format and the agency had to provide ≥1,000 pool and spa inspection records† for 2008. Each agency’s pool inspection data were standardized for analysis and included information on water chemistry, circulation and filtration system, policy and management, and pool setting and type. A violation was defined as an inspection item that did not meet standards set by the jurisdiction’s pool code. CDC developed an algorithm based on facility name to classify pool setting (e.g., "hotel A" was coded as "hotel/motel"). Facility-identifying data then were deleted, and data from individual agencies were aggregated. Denominators in this report vary because pool codes, and therefore inspection items, differed across jurisdictions.

During 2008, inspectors in the 15 jurisdictions conducted a total of 121,020 routine pool inspections. Among the 121,020 inspections, the number of code violations identified ranged from 0 to 28 (median: 1), and 73,953 (61.1%) inspections identified one or more violations. A total of 13,532 (12.1%) of 111,487 inspections identified serious violations that threatened the public’s health and resulted in immediate pool closure. Of 120,975 inspections, 12,917 (10.7%) identified disinfectant level violations; of 113,597 inspections, 10,148 (8.9%) identified pH level violations. Other water chemistry violations§ were documented during 12,328 (12.5%) of 98,907 inspections, with the number identified per inspection ranging from zero to four. Circulation and filtration violations¶ were documented during 35,327 (35.9%) of 98,361 inspections, with the number identified per inspection ranging from zero to nine. The following violations also were identified: improperly maintained pool log (12,656 [10.9%] of 115,874 inspections), unapproved water test kit used (2,995 [3.3%] of 90,088 inspections), valid pool license not provided and/or posted (741 [2.7%] of 28,007 inspections), and operator training documentation not provided and/or posted (1,542 [18.3%] of 8,439 inspections).

Of the 121,020 inspection records, 59,890 (49.5%) included pool setting data. Among venues with known pool settings, child-care pool inspections had the highest percentage of immediate closures (17.2%), followed by hotel/motel and apartment/condominium pool inspections (15.3% and 12.4% respectively). Apartment/condominium and hotel/motel pool inspections had the highest percentage of disinfectant level violations (13.1% and 12.8%, respectively). Child-care and apartment/condominium pool inspections had the highest percentage of pH level violations (11.8% and 10.0%, respectively). Approximately 35% of inspections of apartment/condominium pools, hotel/motel pools, and water parks identified circulation and filtration violations.

Of the 121,020 inspection records, 113,632 (93.9%) included pool type data. Interactive fountain inspections had the highest percentage of immediate closures (17.0%). Kiddie/wading pool inspections had the highest percentage of disinfectant level violations (13.5%), followed by interactive fountain inspections (12.6%). Therapy pool inspections had the lowest percentage of disinfectant and pH level violations but the highest percentage of other water chemistry violations (43.9%). Interactive fountain inspections identified the lowest percentage of circulation and filtration violations (12.8%).