Every fire hydrant in Des Moines is color coded to indicate how much water is available from that hydrant for fire fighting. The bonnet is painted a specific color in accordance with National Fire Prevention Association Standard 291. This color coding allows fire fighters to quickly determine which hydrants in a given area will provide the best flow of water for fighting a fire. The different colors represent the flow available from the hydrant in gallons per minute. The color codes used in Des Moines are as follows:
- Red = 0 to 500 gallons per minute
- Orange = 500 to 1,000 gallons per minute
- Green = more than 1,000 gallons per minute
Des Moines Water Works owns and maintains more than 10,000 fire hydrants in Des Moines and the surrounding areas. Each of the hydrants receives regular maintenance including an annual check every fall to ensure the hydrant has not been damaged and is not standing full of water that could freeze during the winter months, rendering the hydrant unusable in the event of an emergency. In addition, every fire hydrant receives more thorough maintenance every two to three years to ensure the moving parts are well lubricated and in proper working order.
Fire hydrants are actually used more frequently for water system maintenance than for fire fighting. Any time maintenance is performed on the water system, air is allowed to escape from the pipes through the hydrant, and water is flushed from the hydrant to ensure water delivered to customers following maintenance is clear.