Does the ADA cluster rule apply to two porta potties?

Yes, the ADA cluster rule applies to your two portable toilets. The 2010 ADA Standards for Accessible Design state that where multiple single-user portable toilets are clustered at a single location, at least 5 percent of the units in each cluster must be accessible. For a cluster of two units, 5 percent is 0.1 units, but the rule is interpreted to require at least one ADA-compliant portable toilet when you have any cluster.

What the rule means
The term 'cluster' is not defined by a minimum number. If you place two or more single-user portable toilets together to serve an event, that is a cluster. Your two standard units would not be compliant on their own. You must replace one standard unit with an ADA-compliant unit. It must also be identified with the International Symbol of Accessibility.

Why the rule exists
This is not about capacity; it is about providing equivalent access. A person using a wheelchair must have the same opportunity to use a restroom as everyone else. The ADA-compliant unit provides the required clear floor space, grab bars, accessible door hardware, and a higher toilet seat.

For a small public event
Even though your event is small, if it is open to the public, compliance is required. The city permit office is correct to flag this. Your setup for two units on level ground with truck access will now include one accessible unit.

Ask if you have questions about the accessible unit's placement or features.