In 1928, at a meeting of the California League of Municipalities in Long Beach, F.D. Sweger, Chief of Inspections of the Los Angeles City Health Department, and Harold A. Young, Chief of the Los Angeles County Bureau, put their ideas together and decided it would be useful to hold joint city and county meetings and possibly form an organization.

Invitations were sent to ten city and eight county health departments in Southern California and as far north as San Luis Obispo. Thirteen people attended this initial meeting. They went back to their respective departments and on March 1, 1930, a dinner meeting was held at Patriotic Hall in Los Angeles with between 150 and 200 in attendance. It was at this meeting that an association of sanitarians was formed which became the California Association of Sanitarian (CAS). During this meeting, an election was held and J.H. McDermott defeated Walter Mangold in the first election for president.

One of the key functions of the newly formed association was training the new sanitarians entering the field. During the thirties, a Northern California Association was formed. In 1937, Walter Mangold approached the American Public Health Association (APHA) to determine the feasibility of the CAS becoming a section within APHA which would give sanitarians national status. He was told that in order to gain professional recognition, the sanitarians should form their own association.

In 1937, the California Association of Sanitarians, with members from nine states, changed their name and formed the National Association of Sanitarians (NAS) incorporated in California. The association had a printed magazine and four sections (chapters): Northern California, Southern California, San Diego, and Pennsylvania. The first annual meeting of the NAS was held in San Luis Obispo.

The new association received publicity and operating money from the publication of a small booklet titled, "The Sanitation of the Drinking Glass."

By 1970, the NAS was comprised of 41 affiliates, including a California state affiliate known as CAS, and over 5000 members. In 1970, the NAS was renamed the National Environmental Health Association and the CAS affiliate was renamed the California Environmental Health Association (CEHA).