Although chlorination may not be technically required at Centennial, there is no other viable alternative as the water must remain fresh and parasite/bacteria free, as it is a public facility. It's designation of a "beach" by the IDPH does not relieve the city of Naperville of certain "pool" water quality and safety requirements. Quote from the website: "Yes – our staff tests the water 2-3 times daily to monitor chlorine levels and pH balance. We typically follow swimming pool regulations with regard to water quality standards. On a weekly basis, our water is sampled and tested by an independent laboratory to ensure that the water quality is being maintained. "