Fire Hydrants Stock Photo

Known as NFPA 291, it says fire hydrants using public water supply systems should be painted chrome yellow and their tops and caps should indicate the available GPM. Water supply for fire fighting is rated in gallons per minute available. Below 500 GPM should be red, 500 to 999 should be orange, 1000 to 1499 should be green and 1500 or more should be blue. If a hydrant is inoperable, it is suggested it be painted black.