Crews to flush Issaquah water mains for two weeks, starting March 15

Thanks to the unique geology of wells that feed Issaquah's water supply, the City of Issaquah’s Public Works Operations Department will be conducting routine water main flushing over a period of two weeks, starting March 15. Crews will conduct the annual maintenance on the mains in the northwest part of the city. The water lines serve neighborhoods that lie near the Interstate 90 corridor including Lakemont, Montreux, Talus, Pickering, Tibbetts Creek, Gilman and Newport.

By Kendall Watson • March 12, 2010 8:39 pm
Most of Issaquah's drinking water is pumped from four groundwater wells that draw water from the lower Issaquah Valley aquifer from a depth of about 80 feet or more below the ground surface.
Most of Issaquah's drinking water is pumped from four groundwater wells that draw water from the lower Issaquah Valley aquifer from a depth of about 80 feet or more below the ground surface.

Thanks to the unique geology of wells that feed Issaquah’s water supply, the City of Issaquah’s Public Works Operations Department will be conducting routine water main flushing over a period of two weeks, starting March 15.

Crews will conduct the annual maintenance on the mains in the northwest part of the city. The water lines serve neighborhoods that lie near the Interstate 90 corridor including Lakemont, Montreux, Talus, Pickering, Tibbetts Creek, Gilman and Newport.

Work on the mains will be conducted in the early morning hours, from midnight to 6:30 a.m., Monday through Thursday for two weeks.

Water Operations manager Issaquah Greg Keith said most utility customers will not notice a change in their water service during this annual maintenance, but agreed that residents should avoid using their water during the flushing because sediment could enter residential plumbing.

According to the city, about two million gallons of well water is pumped daily to supply the majority of Issaquah’s drinking water needs. The annual maintenance is necessary because of a higher-than-average level of manganese present in wells that serve the city’s northwestern neighborhoods. The greyish-pink metal collects as sediment in the water mains and, if not flushed, discolor the water with a brownish or reddish hue. While ingesting the elevated levels manganese in Issaquah’s well water is not consider harmful, the discolored water could cause possible dark staining in laundry.

“We flushed last winter,” Keith said. “We didn’t have any problems this year. Our preventive maintence seems to be working.”

Public Works will not post notices for the work, but Keith said crews will be clearly visible wearing reflective vests and using clearly marked vehicles. Local businesses that operate on a 24-hour basis in the area, such as the Holiday Inn, Motel 6 and Swedish Medical Center/Issaquah, have already been notified.

The water will be dechlorinated, kept off roadways and allowed to flow instead into ditches, sewers and storm retention ponds.

Residents experiencing changes in water service or with any questions or concerns are encouraged to contact Greg Keith at 425-837-3470 from 7:30 a.m. to 4 p.m. during regular city business hours. Before or after working hours, call the Issaquah Police Department at 425-837-3200 tpo find out what areas the city is working in.