Water system flushing, often referred to as flushing, is the process by which the insides of the water distribution system are cleaned. High velocity water is flushed through the system to remove minerals that have built up inside the pipes. Periodic flushing helps maintain water quality and keeps the system operating as engineered.
Most water systems are flushed annually or biannually; however, some systems, or portions of systems, require more frequent flushing.
KPUD often flushes residential water systems during the day when a majority of residents are at work. Much larger systems, which include commercial establishments, at usually flushed at night to minimize impacts to our customers.
When flushing water lines or mains an operator opens a blow off valve or water hydrant to flow water at a high rate to create enough velocity to strip sediment that collects on the inside of the piping walls.
Prior to flushing, we notify the community via roadside sandwich boards and posts on our website. During flushing, customers might experience lower pressure and/or discolored water. This discolored water is caused by minerals that have been flushed from inside the water mains.
Because flushing can result in discolored water at customers' homes, people should refrain from doing laundry when flushing is taking place. Customers with water filters might want to bypass the filter during flushing to prevent it being fouled. Further, any customer on dialysis should not use discolored water resulting from flushing. These customers should contact Kitsap PUD so that we are aware of their situation and can notify them in advance of any flushing.
Customers who experience discolored water are advised to flush off their service line by running a cold water tap until the water clears. If the water does not clear after several minutes, please call our office to report the matter. Note: Our Operations Department recommends customers utilize flushing events to conduct a "Spring cleaning" of their service line. When customers see that a system flush has wrapped up, they should make a point of conducting a mini-flush of their individual line. In this, the customer should make it routine to run the outside hosebib closest to their service line, fully open, until the water runs clear. In this way, the entire water system, including service line, receives the same maintenance.
As mentioned, the minerals that build up in our water mains are naturally occurring in our groundwater. These are, primarily, iron and manganese. While these minerals pose aesthetic concerns (discolored water, stained fixtures) they are not recognized as posing health risks.
All of KPUD's water systems are served by groundwater. Groundwater is, typically, high in mineral content; especially iron and manganese. These minerals build up inside the distribution mains.