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Hydrants

Hydrants are a vital part of our water system. They keep water moving safely through more than 2,000 miles of underground pipes and are critical for firefighters during emergencies.

Milwaukee Water Works (MWW) owns and maintains about 20,000 fire hydrants in Milwaukee, Greenfield, St. Francis, and Hales Corners. 

Hydrant Inspections, Flushing, and Maintenance

Each year, MWW crews inspect and flush about 10,000 hydrants during the warmer months. These routine activities help maintain system reliability, support water quality, and ensure hydrants are ready for emergency use.

Flushing is a normal process that:

  • Keeps water moving through the system to maintain freshness
  • Supports safe, clean drinking water
  • Ensures hydrants are operational for firefighting

During inspections, crews:

  • Fully open and flush hydrants to remove stagnant water
  • Test hydrants under pressure to check for leaks
  • Verify proper shutoff and drainage
  • Inspect moving parts for wear

Crews also collect water samples to confirm water quality standards are met, including flow rate, clarity, and chlorine levels required by the Wisconsin Department of Natural Resources.

If a hydrant is not working properly, it is reported for repair right away. The local fire department is also notified until the hydrant is fixed.

Hydrant painting is part of routine maintenance. Hydrants are repainted every 8–10 years to help prevent rust and maintain visibility. Most hydrants are painted red, while color markings help crews identify water main size, service conditions, or special use.

Hydrant Colors and Markings

Hydrants are marked with plastic color rings to help crews and firefighters quickly understand their status:

  • Yellow – Out of service due to a problem. The fire department is notified, and repair crews are assigned.
  • White – For fire department use only. These hydrants may hold water after use and must be checked before freezing weather.
  • Lime Green – In use under permit with approved backflow prevention.
  • Green – Private hydrant not owned or maintained by MWW.
  • Blue – Located at the end of a dead-end main and receive additional flushing each year.

Hydrant Painting and Color Information

  • Hydrants are repainted every 8–10 years to help prevent rust and maintain visibility. Most hydrants are painted the traditional red.
  • Yellow hydrants indicate a connection to a water main that may not be directly in front of the hydrant.
  • Hydrants with green tops are connected to larger water mains (12 inches or larger). This helps firefighters quickly identify hydrants that can provide the most water during emergencies.
  • Color markings on hydrants also help fire crews quickly understand hydrant status and water system conditions.

Hydrant Care and Public Safety

Keep Hydrants Accessible for Emergency Use

Fire hydrants are critical to firefighting operations and must remain accessible.

  • Do not park vehicles in front of or within a few feet of a hydrant.
  • Keep hydrants clear of snow, ice, landscaping, and other obstructions.
  • Do not place or store materials near hydrants.
  • Clear access to hydrants helps fire crews respond quickly and safely during emergencies.

You may see water flowing into the street during hydrant flushing. This is a normal part of the process and not a cause for concern.

What Happens to Old Hydrants?

When hydrants are replaced, MWW recycles them in accordance with state regulations, which prevent utilities from selling hydrants to the public. Occasionally, old hydrants may be donated to the Milwaukee Fire Department for fundraising events.