An Upland institution is closing. Mitchell’s Plumbing was founded in 1938 and has been at 2nd and D streets downtown since 1942. But after the death of the third-generation owner, a year after his brother, there were no Mitchells involved in the business. So the family decided to shut it down. The last day is June 28. Sunday’s column tells the Mitchell’s story, as well as sharing one of my own anecdotes about the business.