Smith's Marketplace
5448 Daybreak Pkwy, Herriman, UT
100% positive
Directions: When entering the store, turn left and just continue straight towards the pharmacy. The bathrooms are once again on the left. There are two stalls, both unisex, and they lock. Handicap accessible (I believe--I'm abled so I don't know for sure).
Comments: No idea if you must be a paying customer or not. To be safe, browse a bit.