As described in our maintenance section, fire hydrants are periodically opened to flush water mains in the system. Additionally, Fire Department and Public Services personnel routinely use hydrants to make assessments of water pressure and flow or for fires.
These actions, as well as some construction activities, may result in brief periods during which you may observe moderate discoloration in your tap water caused by fine sediment particles dislodged from the main line. The reddish discoloration you may see in your water is caused by small amounts of iron compounds flushing out of the system. These iron compounds are not hazardous.
The discoloration affects only the appearance of the water; it does not affect water quality. For more information about this issue, see hydrants.
Once in a while water from the tap comes out looking cloudy or milky. After a few seconds it is gone. The cloudiness might be caused by the water in the pipes being under more pressure than the water in the glass, but is more likely due to tiny air bubbles in the water. Like any bubble, the air rises to the top and goes into the air.
In the late fall and winter months, the water that enters your home can be quite cold. Cold water holds more air than warm water. When this cold water enters your home plumbing, it is exposed to significantly warmer temperatures. This change in temperature causes dissolved oxygen to escape in the form of "micro-bubbles." These bubbles can give water a cloudy appearance. If a glass of this water is allowed to sit for a short period of time the cloudy effect will dissipate. The air bubbles in the water are completely harmless.