what is the difference between a red fire hydrant and a yellow fire hydrant?
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. Below 500GPM should be red, 500-999 GPM should be orange, 1000-1499 GPM should be green, and 1500 GPM or more should be blue.