The nation's first comprehensive guidelines for public pool operations have been released by the Centers for Disease Control and Prevention.

The Model Aquatic Health Code offers directions for public pool operators to follow, in order to better ensure swimmers remain healthy and safe, which state and local health departments can use when creating or updating their own public pool regulations, according to an agency press release.

The code provides advice on safe operation of public aquatic facilities, including design and construction, water filtration and disinfection, safety, ventilation and air quality and staff training.

Americans, the CDCP says, make more than 300 million visits to public swimming pools each year.

Swimming pool-associated outbreaks, mostly of diarrhea, have significantly increased during the past 20 years. In 2009-2010, the latest period analyzed, outbreaks involving 57 pools sickened more than 1,000 people and sent 40 swimmers to the hospital.

As well, injuries caused by the improper use of pool chemicals led to about 5,000 emergency room visits in 2012 alone.

An average of about 4,000 swimmers drown each year, with children younger than 5 years the most frequent victims.

More than two-thirds of local health departments inspect public pools each year. Studies of data from more than 120,000 pool inspections found that 1 in 8 public pools were closed immediately because of health and safety issues. The Model Aquatic Health Code is intended to serve as a blueprint for a healthy and safe public swimming environment.

The CDC explains all public swimming pool codes and legislation are developed at the state or local level, leading to a great variability in standards -- as a result requiring each locality to spend significant blocks of time and resources to updating pool codes regularly.

Through the collaboration between the CDCP, state and local public health departments, the aquatics sector and academic experts, the MAHC was developed to provide the latest guidance on safely building and operating pools.

The first edition of the MAHC was published after work with more than 150 experts and review of more than 4,400 public comments.

For more information about recreational water illnesses and healthy swimming, online users may visit: www.cdc.gov/healthyswimming.