Tanks are made of Section 2 materials, sit on bases designed for their full weight, metal tanks are isolated from their supports, no load passes to attached pipes, tanks are accessible for inspection and maintenance, covered against dust and water and animals, seismically restrained in New Zealand, capacity is measured below the overflow, access considers confined space rules with ladders for deep tanks, safe-trays are fitted where required and drinking tanks are never under sanitary or non-drinking pipes (2003 text).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.