Under the ADA Standards, where portable units are grouped together for the public, at least 5 percent of the units in each group, and never fewer than one, must be accessible and marked with the International Symbol of Accessibility. Units used only by construction workers on a construction site are exempt.
Event permits can ask for more. The City of West Palm Beach notes in its special event application that it may require portable restrooms, including accessible units, depending on crowd size and event history. For festivals, markets and public events anywhere in Palm Beach County, plan accessible units into the count from the start. Our Guide to How Many Porta Potties You Need includes the numbers.
Where the unit goes matters as much as the unit. Place accessible restrooms on firm, level ground with a smooth route from the event, not across grass, gravel or a curb.