Since that time, the pollution picture has become more complex, with myriad issues related to toxic contamination. In addition to point sources, the reality of non-point source pollution has risen to the forefront. This type of pollution is essentially runoff, from the rain and water that courses across farms, parking lots, lawns, and any lands that drain into local creeks or rivers. Consequently, runoff can carry with it whatever happens to be on the land, including oil based pollution from streets and parking lots, pesticides or manure from fields, and other nonpoint source pollutants that are carried into the Willamette River system each and every day.
The Willamette River is on the Clean Water Act 303 (d) list for violations of water quality standards including temperature, bacteria, and mercury. The Oregon Department of Environmental Quality sets standards and aims to regulate river pollution through its statewide permitting program. The river also has been impacted by localized pollution issues, from the Combined Sewer Overflows (CSOs) in the City of Portland when it rains too much (although the Big Pipe Project has vastly improved this issue), to the Portland Harbor Superfund site, where a great many properties along the river have highly contaminated soils from industrial activity going back over 100 years.