While one cannot control the water chemistry, he/she can control personal hygiene and facility cleanliness. Giardia and cryptosporidium (crypto) are only two of the many recreational water illnesses (RWIs) that can turn happy swim memories into serious illness situations. In this article, the author discusses three factors that determine how healthy--or unhealthy--any swimming pool is for a family. These include: (1) personal hygiene of the swimmers; (2) cleanliness of the facility; and (3) chemical balance of the water.