Pioneers William Overton and Asa Lovejoy discovered the site for Portland on an 1840s canoe expedition. By 1862, residents recognized that private wells wouldn’t suffice to sustain the growing population. So, they established a system to pipe water to residents from Carruthers Creek, Balch Creek, and Willamette River. By 1886, waste from upstream factories and towns caused a pollution crisis. City planners set about creating a gravity-flow system from Bull Run River and the surrounding watershed, which would provide enough drinking water for years to come.

Once city officials had established an abundant source from the Bull Run River, they turned their attention to protecting the Portland water supply from contamination from the local logging industry. The Forest Reserve Act of 1891 was enacted to prohibit settlement in the 142,000-acre Bull Run National Forest, which surrounds The Bull Run River. In 1904, President Theodore Roosevelt signed into law the Bull Run Trespass Act to further protect the reserve and water supply.

Today, The Bull Run Watershed, located in the Mt. Hood National Forest, provides clean drinking water to a quarter of Oregon’s population. Portland groundwater supply provides drinking water from 25 active wells located in 3 different aquifers which can produce up to 80 million gallons of water per day.

According to a recent Portland Water Quality report, Portland drinking water undergoes a 3-step treatment process: 1) Chlorine, added for disinfection. 2) Ammonia, added to form chloramines, 3) Sodium hydroxide, added to increase pH of the water and reduce corrosion of plumbing materials.

The water from these sources travels through above ground pipes to concrete reservoirs and tanks throughout the city, some of which date from the early 1900s! The raw water from Bull Run Watershed is not filtered before distribution and has several naturally occurring contaminants, like sediment and bacteria, as well as the above-mentioned added contaminants like chlorine, ammonia, and sodium hydroxide.