Manteca in May reduced its per capita water use by 4.9 percent over May 2022 levels.

But with the drought now deepening as it enters its third year that wasn’t enough.

*The South San Joaquin Irrigation District — in a bid to assure a fourth year of drought does not force draconian cutbacks in 2023 — has asked the cities of Manteca, Tracy, and Lathrop to reduce the treated surface water delivers that they contracted for by 20 percent.

*That is happening as underground water use is on the upswing, triggering drops in the water table  that can take years to replenish in the best case scenario.

*State leaders are now warning the request for 15 percent voluntary water use reductions over 2020 levels may become mandatory given how most jurisdictions have fallen short of the established goal to scale back water use.

*Major reservoirs are seriously lagging in terms of average capacity at this year.

*The 4.5 million acre foot Shasta Reservoir was at 48 percent of average for June 2. That reflects 40 percent of its overall capacity.

*Oroville with 3.5 million acre feet of storage was at 58 percent of average for June 2. That reflects 54 percent of its overall capacity.

*New Melones that is critical to the cities of Manteca, Lathrop, and Tracy with a design storage of 2.4 million acre feet was at 57 percent of average historic capacity for June 2. That reflects the reservoir currently being filled only 36 percent of the way.

May trends for Manteca

per capita water use

May water use on an annual basis shows how the city has done over the years when it comes to reducing water use.

The comparisons use per capita or per individual consumption based on the city’s population in the given year and the number of gallons the city delivers throughout the month.

It includes all municipal water use whether it is from city wells or the South San Joaquin Irrigation District surface water treatment plant.

It is water used by the schools, the city to irrigate parks, commercial and business park concerns, industrial users such as Eckert’s Cold Storage that washes bell peppers for processing, hospitals, as well as residential users.

Manteca used 534 million gallons of water in May of 2013. With a population of 71,000 nine years ago that translated into 242.6 gallons per capita per day with all residential, commercial, school, and city use — primarily in parks — tossed in.

That figure was higher at the end of the 20th century before the widespread use of low-flow showerheads, low-water use toilets and washing machines as well as other conservation measures became the norm.

May per capita water consumption in May of 2019 — at the end of the last drought period — had dropped to 151 gallons as residents and the city overall complied with the mandatory 15 percent reduction ordered by the state.

Water use bounced back up to 188.46 gallons in 2020 when the city had 85,000 residents and after the drought ended.

Last month the per capita May use was down to 179.1 gallons with 88,000 residents for a 4.9 percent drop over May 2020.

The state had asked for a voluntary reduction statewide of 15 percent.

While dropping reservoir levels are a highly visible sign of the drought, the impact on the underground aquifer Manteca pumps from can’t be seen.

That aquifer has dropped three feet plus in some spots in recent years.

Last month Manteca got 45.8 percent of its water from underground sources or 224.7 million gallons.

In May of 2019 Manteca tapped into the aquifer for 119 million gallons of water.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com