San Joaquin Valley – Modesto
Statistics
- Basin Name
- San Joaquin Valley – Modesto
- Basin Number
- 5-022.02
- SGMA Basin Priority
- High
- Critically Overdrafted
- No
- Hydrologic Region Name
- San Joaquin River
- Counties
- Stanislaus
At-A-Glance
Located in California’s San Joaquin River hydrologic region, the San Joaquin Valley – Modesto is 245,253 acres in size. This High priority basin is home to an estimated 292,341 people (2010 value), which have been at a rate of 17.66.
San Joaquin Valley – Modesto is a(n) basin with approximately 4296 wells, of which approximately 197 are water supply wells. Groundwater accounts for approximately 37.65 percent of the basin’s water supply.

Basin Notes
2003: Bulletin 118 basin description
2014: CASGEM basin prioritization – high. Comment: Water quality degradation due to industrial and agricultural practices.
2018: Draft basin prioritization – high. Comments: 1) CASGEM/WDL/GWIDS: Longterm hydrographs show groundwater level decline. Source: DWR 2) In Appendix A – Selected General Plans for the San Joaquin River Watershed, Modesto depends heavily on groundwater, but is cooperating with the Modesto Irrigation District to develop a new surface water supply that will be used to stabilize groundwater overdraft problems.
2018 Final Basin Prioritization: Basin status remains unchanged at high priority.