The Maryville Treatment Center has its own water tower, but Maryville provides the water supply. The water tower is on the highest point of the prison property (about 1,118 feet at its base compared to 1,103 at the base of the distinctive 1947 motherhouse bell tower. In my initial research I could not find the height of the bell tower or water tower (or tower capacity)
For many years, I thought this was because prisons tried to keep their water systems separate from local communities in case there was a dispute between the entities, but that is not the case. Here’s a deep dive using AI.

