Hand Wash Stations and Potable Water
Tell the OSHA inspector you have consulted the Portable Sanitation Association International (PSAI), the world’s largest trade and standard-developing organization for the industry, regarding potable water in hand sinks. The PSAI recognizes that the OSHA standard requires "potable water." However, since the OSHA standard was developed in the 1970s, the evolution of portable sanitation industry standards has deemed any water — however clean — that does not come from a food grade truck to be “non-potable.” This designation as “non-potable" is correct even though the water used in hand wash equipment typically transfers from a potable source into the service truck for delivery to the site. Once potable water has been placed into a non-food grade service truck, it ceases to be potable.
Because the clean water on a service truck is technically non-potable, the PSAI thus recommends that stickers such as the ones the OSHA inspector observed on your site be placed on hand wash units as an industry best practice. The PSAI can verify that food grade water trucks are not used for servicing portable sanitation equipment, and even if they were, the nature of that portable equipment would generally make the water unsuitable for drinking. The water is, however, clean and safe for hand washing and all other external uses.