There are five significant water bodies in Mountlake Terrace.
Lake Ballinger is popular among Mountlake Terrace residents for fishing, kayaking, canoeing, and swimming. The formation of Lake Ballinger likely occurred as a result of the Frazier glaciation retreat approximately 15,000 years ago. The upper watershed is 3300 acres, including parts of Lynnwood, Edmonds, Mountlake Terrace, Shoreline, and unincorporated Snohomish County.
Hall Creek originates at Hall Lake in Lynnwood, an unusual kettle lake formation that is 70 to 80 feet deep. Hall Creek produces 65 percent of the inflow to Lake Ballinger. It is estimated that flows to Lake Ballinger from Hall Creek have increased 40-50% over pre-development forested flows.
Water leaving Lake Ballinger is carried by McAleer Creek through the Nile Golf Course and under I-5, through Lake Forest Park to Lake Washington. Significant flood abatement work has been completed along McAleer Creek by Mountlake Terrace in the Nile Golf Course. Several undersized culverts, which were restricting waterflow, were replaced by bridges in 2015. Lake Forest Park removed a substantial number of fish barriers through the years along McAleer Creek, between Lake Washington and the I-5 culvert.
Lyon Creek, in the eastern part of Mountlake Terrace, is the largest watershed in the city at 2,600 acres. Lyon Creek watershed extends into Brier, unincorporated Snohomish County, and Lake Forest Park. The northwest branch of Lyon Creek runs through the popular Terrace Creek Park. Lyon Creek, like McAleer Creek, flows through Lake Forest Park in King County to Lake Washington.
Scriber Creek drains the northeast portion of Mountlake Terrace, then runs through Brier. Scriber Creek joins Swamp Creek in Snohomish County and eventually joins the Sammamish River in King County, flowing into Lake Washington. Staff from Brier and Mountlake Terrace work together to meet requirements for a fecal coliform control plan for Scriber Creek.