Surface water drainage in Mountlake Terrace is greatly influenced by the urbanized nature of our community as well as that of our surrounding communities. The Hall Creek - Lake Ballinger drainage basin collects stormwater runoff from Mountlake Terrace as well as the cities of Lynnwood, Edmonds and Shoreline. All these areas have experienced expansion of impervious areas with increased development. More impervious areas such as streets, parking lots, and building roofs have led to increased runoff to surface streams and lakes. This increased runoff also carries with it pollutants picked up from streets, lawns, construction sites and commercial properties. Common water quality problems that can occur as a result of surface water runoff include depleted dissolved oxygen levels, increased water temperature and sedimentation. The presence of excess nutrients, fecal matter, hydrocarbons, heavy metals and pesticides are also things that can negatively affect water quality.

The City of Mountlake Terrace has implemented a number of measures to help minimize and reduce the impact of urban runoff pollutants in our surface streams and lakes. All new development and redevelopment projects must meet state standards for stormwater runoff during the construction portion of the project. Post development runoff must also meet state standards for runoff quantity and quality through the use of detention ponds and vaults, water quality filters and grass lined swale or soil infiltration trenches. In 2007 and 2008, the City implemented a program to actively filter stormwater pollutants from selected areas of the City that are tributary to Hall Creek and Lake Ballinger.