Non-drinking pipes are purple (integral or sleeved or taped) in the specified colour range, buried ones carry marker tape with the recycled water warning, fittings may be purple, external hose taps carry a warning or prohibition sign, have removable handles below a set height and are purple, and all other outlets carry the sign (2003 text, requirement area kept in 2021 Clauses 9.6 and 9.7).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.