Functional school planning has long been considered a fundamental concept of school design. However. in planning educational facilities, it is also important to include the dimensions of comfort, convenience and healthfulness. The school lavatories and drinking fountains are one of most crucial elements for the recent changing face in healthful school design, but the number of lavatories and drinking fountains in most schools may not be sufficient to meet current needs. This study aims to suggest a guideline in designing school sanitary fixture and propose the optimal number of lavatories and drinking fountains regarded to age and sex. The survey is conducted through questionnaires collected from 998 respondents including 300 teachers In ChungNam province. Based on the results of the survey and a formulae, it is suggested that the number of lavatories be required by ratio of 30 boys per unit fixture and 22 girls per unit fixture in the elementary, middle and high school. It is also suggested that the number of drinking fountains be required by ratio of 65 students per unit fixture. The formulae proposed in this paper can be used for other plumbing fixtures required in school facilities.