Below is the Massachusetts plumbing code law for water temperature in a restroom sink. As noted there is a maximum temperature but not a minimum.
248 CMR 10.00: Uniform State Plumbing Code
(CMR) Code of Massachusetts Regulations
10.14: Water Supply and the Water Distribution System
(3) Conservation of Water.
(a) Conservation of Hot Water.
1. Lavatory faucets in public toilet facilities shall:
b, Be equipped or installed with devices which limit the outlet temperature to a maximum of 110EF.
We set the school temperature to be about 80 -95 in the restrooms. The logic is that students coming from the outside with cold hands could easily get burned or the sensation of burning if the temperature was any higher.