> by the 1950's the Seattle city sewage system was dumping up to 50 million gall...

> by the 1950's the Seattle city sewage system was dumping up to 50 million gallons of sewage into the Puget sound (per day).

Seattle started building water treatment plants in 1961 and they entered service throughout the 1960s: https://kingcounty.gov/en/dept/dnrp/waste-services/wastewate...

Meanwhile, Victoria, BC (Canada) continued to dump raw sewage into the ocean until 2021: https://www.cbc.ca/news/canada/british-columbia/victoria-sew...