bigdogger wrote:
I really don't know of an RV repair facility that wouldn't have it's own restrooms. Employees are assuredly told not to use a customer's restrooms. Even if an employee stepped out of line and used a toilet a single use wouldn't have put much in the tank. It is entirely possible that the shop was correct in that driving the rig after the tank had been drained would loosen some additional debris.
Would the service you had done require anyone to run any water? Things like de-winterizing, fixing any water lines, pumps, valves, tanks, water heaters, etc. would all require running all the water lines to remove any air in those lines after servicing. Even electrical repairs may have resulted in the techs checking that all systems were working including water puImps and electric valves.
I actually had a coupling in a waterline repaired and they did run a lot of water to check for leaks.