White Slough Water Pollution Control Plant

Ever wondered where your water goes after you flush the toilet or drain the sink? Lodi’s White Slough Water Pollution Control Plant — approximately 10 miles southwest of Lodi Lake — treats your "wastewater," transforming it into clean water. Then, the plant either discharges that water into the Mokelumne River or places it back into the city's water supply as non-potable water for uses like irrigation.

Why do we need this kind of plant? It’s not just a good idea; it’s required by federal law. The 1972 Clean Water Act mandates that all cities/towns treat wastewater to protect the health of our waterways. California enforces these regulations under its own State law, which adds even stricter requirements, but there’s one big challenge: the State doesn’t provide funding to help cities like Lodi meet these federal requirements. This is known as an “unfunded mandate,” meaning cities are left to figure out how to pay for the infrastructure and operations on their own.

At the White Slough Water Pollution Control Plant, the treatment process starts by removing wipes, rags and debris — yes, even “flushable” wipes that can clog the system. Next, the plant skims fats, oils, and grease (known by the acronym FOG) from the water, and microorganisms in aeration basins break down organic waste.

Any remaining solids then become fertilizer for 1,000 acres of city-owned farmland, where crops are grown for animal feed. The next steps — filtration and UV disinfection — ensure the water is clean and safe. Finally, the water quality lab at White Slough tests the treated water to ensure it’s safe for release. They also conduct daily checks to confirm that Lodi Lake’s water is safe to swim in.