Officials in Portland are warning residents not to paint fire hydrants in the city.

The Portland Water District says firefighters have recently encountered fire hydrants that were painted over, which they say could jeopardize public safety because the hydrants are color-coded according to water flow available at that location.

Firefighters also make use of specialized paint that makes it easier to find the hydrants in the dark.

The water district will be placing decals on hydrants informing the public about the importance of the color-coding system.