Handwashing sinks minimum temperature: 100 degrees fahrenheit

Reference Page 15: https://www.sandiegocounty.gov/content/dam/sdc/awm/docs/DEH%20Temporary%20Event%20Organizer%20632%20rev%2004-25-14%20FILLABLE.pdf

You can use a cambro + a 5 gallon jug + a pump soap + a paper towel.  Very simple setup.