7111 Bulk water systems fed from natural sources (0) Bulk water supply systems from subterranean sources, ponds, lakes and rivers, to provide water to systems reticulating water 7112 Bulk water storage tanks (5) Storage tanks for water supply 7113 Protective treatment to water storage tanks (0) Protective treatment to water storage tanks to retain water and to protect against deterioration and contamination 7114 Chemical treatment - Potable water (0) A plant to treat a water source to render it potable or to improve the quality of potable water