Lodi's Water Supply

Next time you take a sip of water in Lodi, think about this: you're drinking a blend of river water and 40-year-old "groundwater." The city’s drinking water comes from two main sources: the Mokelumne River and groundwater. After it rains, it takes 40 years for the surface water to percolate through the soil to underground aquifers, where wells then draw it up for use — this is called groundwater.

Unfortunately, due to over-extraction, there’s no longer enough groundwater to meet demand. Since 2003, the city has purchased 6,000 "acre-feet" of Mokelumne River water from the Woodbridge Irrigation District (WID) annually, at a cost of $1.2 million per year. WID has the oldest water rights on the Mokelumne River, meaning it's allowed to use or sell water from the river. Most cities along the river have no such access, so the City of Lodi could not draw water from the river without purchasing it.

To put it in perspective, one acre-foot of water covers an entire football field with one foot of water, and the city consumes 14,000 of these acre-feet per year. Water from the river flows to Lodi Lake’s treatment plant, where it’s cleaned and blended with groundwater for distribution. This treated river water makes up 40% of Lodi’s drinking water.