Count simultaneous users and time on site
For a crew, identify the people working at the same time and whether shifts overlap. For an event, give expected attendance and how long guests remain. Total invitations or the total number of contractors involved in a project may not describe actual peak use.
Account for the busiest period
A break in a programme or the end of a shift can concentrate demand. Explain when those peaks occur. Food and drink service, long stays and the distance to existing bathrooms also belong in the discussion.
Count only facilities people can actually use
An existing bathroom should not be counted if it is locked, too far away, reserved for someone else or closed during part of the rental. Confirm access with the property manager, including any restrictions for contractors or event guests.
Consider the service plan and equipment mix
Quantity, servicing, accessible units and handwashing work together. Ask the responsible organiser or site representative to review applicable requirements with the provider. Do not apply a simplified worker ratio or event chart to every situation.