Why Does the City of San Luis Obispo “Flush” Water Mains?
Water main flushing is a routine operation that results in a well maintained water system. It is an industry wide Best Management Practice. Flushing water mains improves water quality by removing sediment that slowly builds up in the mains over time. During this activity, water moves through the water mains at higher than normal velocity, scouring them to remove this build up, which is then flushed out of fire hydrants in a systematic approach.
The City’s water distribution system is made up of 16 pressure zones, 1,900 fire hydrants, and 5,334 isolation valves. The City’s Water Distribution- Field Operations Crew is responsible for exercising those valves and flushing the distribution system while operating and inspecting the fire hydrants. The entire City is covered on a rotational basis every 3-5 years.
Flushing will generally take place between 8 am and 4 pm for most neighborhoods. There may be a slight drop in pressure or noticeable discoloration of the water from the minerals and sediments that are being flushed out. These minerals are not harmful to your health. If discoloration occurs at your home or business, open your cold water tap closest to the water main, usually an outside hose bib, and run the water for a few minutes until clear.
Avoid using hot water during flushing operations in your neighborhood, as discolored water could be drawn into the hot water system. It is also advised that you make sure your water is clear before doing laundry or other projects for which discolored water could cause problems. Water service should not be disrupted during the flushing process.
During flushing operations, residents may hear water discharging with force from fire hydrants and see water flowing in the street. Road travelers are asked to take extra care during this time and watch for field crews. Safety, regulatory, and logistical considerations prevent the flushed water from being captured and reused.
Since valve exercising and flushing generally results in minimal impact to a small area crews will place signs in the area as the maintenance is being performed.
Water distribution flushing is a normal and necessary part of maintaining a safe and reliable drinking water system. For more information, contact: Marcus Henderson - Water Distribution System Supervisor (805) 781-7035