Lodi's Water Supply Status and Growth Plan
Lodi faces a complex water supply scenario as it pursues ambitious growth plans over the next five years while managing significant groundwater challenges in the critically overdrafted Eastern San Joaquin Subbasin. The city's diversified water portfolio provides near-term stability, but long-term sustainability requires careful management of both supply and demand.
Current Water Supply Portfolio
Groundwater Supply
Lodi operates 28 groundwater production wells with a total pumping capacity of 35,200 gallons per minute, currently providing 50% of the city's water supply. However, this groundwater supply faces serious sustainability challenges as the city overlies the Eastern San Joaquin Subbasin, which the California Department of Water Resources has designated as critically overdrafted.
The subbasin experiences chronic groundwater level declines with an estimated regional overdraft of 160,000 acre-feet per year. Poor-quality groundwater has been migrating eastward along a 16-mile front, bringing saltwater intrusion and elevated salinity levels. Additionally, Lodi continues addressing TCE and PCE contamination in north and central areas of the city, with nine wells equipped with Granular Activated Carbon filtration systems.
Surface Water Supply
Since 2012, Lodi's Surface Water Treatment Plant has provided approximately 50% of the city's drinking water. The facility has a design capacity of 8 million gallons per day (MGD) with the ability to produce 10 MGD. The plant treats water from the Mokelumne River through a 40-year contract with Woodbridge Irrigation District (WID) allowing the city to purchase up to 6,000 acre-feet per year through 2047.
A significant advantage for Lodi is its banked water storage of 53,534 acre-feet accumulated since 2003, when the city couldn't immediately utilize its full WID allocation. This banked supply provides crucial drought resilience and emergency water availability.
Recycled Water Potential
The White Slough Water Pollution Control Facility has a treatment capacity of 8.5 MGD and currently produces recycled water used exclusively for agricultural irrigation. The 2008 Recycled Water Master Plan identified potential urban uses totaling 12,696 acre-feet per year, including parks, schools, and commercial applications.
Growth Plan Analysis and Water Demand Projections
Five-Year Growth Targets (2025-2030)
Westside Vision: This highest priority development includes 800-1,000 residential units in a mixed-use community, with annexation applications already in progress. Water demand impact is estimated at 800 acre-feet annually.
Eastside Vision: Focuses on light manufacturing and technology businesses with mixed-use residential components, targeting completion by 2030. Estimated additional water demand of 500 acre-feet annually.
South Study Area: The most ambitious component proposing 3,000 housing units plus educational institutions and commercial development on 800 acres. This represents 3,000 acre-feet annually in additional demand but is considered a long-term development beyond the five-year timeframe.
Infrastructure Requirements
The city's General Plan identifies critical infrastructure needs including a 36-inch transmission main from the surface water treatment plant to Mills Avenue, with extensions to serve western growth areas. Additional groundwater wells will be required in southern and eastern areas, along with water storage tanks for new development.
Water Supply and Demand Analysis
Water Supply Adequacy Assessment
Near-Term Outlook (2025-2030)
Current analysis shows Lodi maintains adequate water supply for planned five-year growth. With current demand at approximately 25,000 acre-feet annually and reliable supply of 30,860 acre-feet per year, the city has a 5,860 acre-feet surplus.
The Westside Vision development would increase demand to 25,800 acre-feet annually, maintaining a 5,060 acre-feet surplus. Even with all growth areas developed by 2035 (estimated 29,500 acre-feet demand), the city would retain a 1,360 acre-feet surplus under normal water year conditions.
Long-Term Challenges
Full buildout scenarios present more significant challenges. The General Plan projects ultimate demand of 32,710 acre-feet per year to serve a population of 99,500 residents. During normal years, this would create a marginal balance, while dry year conditions could result in a 4,040 acre-feet deficit, meeting only 86% of demand.
Current Water Supply Portfolio
| Water Source | Current Capacity | Supply Percentage | Status 2024 | Future Reliability |
|---|---|---|---|---|
| Groundwater Wells (28 total) | 35.2 MGD | 50% | At risk - ESJ subbasin critically overdrafted | Declining - requires management |
| Surface Water Treatment Plant | 10.0 MGD | 50% | Operational since 2012 | Stable with WID contract |
| Mokelumne River (WID Contract) | 10.7 MGD | Part of Surface | Contract through 2047 | Stable through 2047 |
| Banked Water Storage | 53,534 AF | Emergency/Dry Year | Available | Available for dry years |
| Recycled Water (White Slough WPCF) | 8.5 MGD | Non-potable only | Agricultural use only | Potential urban expansion |
Growth Projections (Next 5-10 Years)
| Development Area | Housing Units | Timeline | Water Demand Impact (AFY) | Infrastructure Required |
|---|---|---|---|---|
| Westside Vision | 800-1,000 | 2025-2027 (in progress) | 800 | Distribution extensions |
| Eastside Vision | Mixed-use/Industrial | 2025-2030 | 500 | Industrial water supply |
| South Study Area | 3,000 | 2030+ (long-term) | 3,000 | Major transmission mains |
| Existing City Infill | Infill development | Ongoing | 1,000 | System upgrades |
| General Plan Full Buildout | Total capacity for 99,500 residents | 2040-2050 | 32,710 | Additional treatment capacity |
Water Supply vs Demand Scenarios
| Scenario | Demand (AFY) | Supply (AFY) | Balance | Supply Adequacy |
|---|---|---|---|---|
| Current 2024 | 25,000 | 30,860 | +5,860 surplus | Adequate surplus |
| Westside Vision (2027) | 25,800 | 30,860 | +5,060 surplus | Adequate surplus |
| All Growth Areas (2035) | 29,500 | 30,860 | +1,360 surplus | Adequate surplus |
| Full Buildout Normal Year | 32,710 | 30,860 | -1,850 deficit | Marginal |
| Full Buildout Dry Year | 32,710 | 25,310 | -7,400 deficit | Shortage (86% of demand met) |
Critical Risk Factors
Eastern San Joaquin Subbasin Sustainability: The January 2025 update to the Eastern San Joaquin Groundwater Sustainability Plan aims to address DWR's recommended corrective actions. The plan must demonstrate how to achieve sustainability by 2040, requiring significant interventions including demand reduction, alternative water supplies, and managed aquifer recharge.
WID Contract Dependency: Lodi's surface water supply depends on the WID contract expiring in 2047. Recent regional water purchase agreements, such as the 2025 agreement between North San Joaquin Water Conservation District and WID for 3,000 acre-feet, demonstrate increasing competition for Mokelumne River water.
Water Quality Management: Ongoing contamination issues require continued monitoring and treatment. The city has secured funding through insurance settlements for TCE/PCE cleanup, but long-term groundwater quality protection remains essential.
Strategic Recommendations
Supply Diversification
Lodi should prioritize expanding recycled water use for urban applications, potentially reducing potable water demand by 1,731 acre-feet annually for parks, schools, and median strips. This would provide additional supply margin for growth while reducing pressure on both groundwater and surface water sources.
Phased Development Approach
The city's existing Growth Management Allocation Ordinance provides an effective framework for managing development pace. Prioritizing the Westside Vision for immediate implementation while deferring the South Study Area until supply security improves aligns with both water supply constraints and market realities.
Regional Coordination
Active participation in the Eastern San Joaquin Groundwater Authority remains critical for long-term groundwater sustainability. The upcoming GSP update must include concrete projects and management actions to address the subbasin's 160,000 acre-feet per year overdraft.
Infrastructure Investment
Priority should focus on completing the Phase 1 transmission main and distribution system improvements to support near-term growth areas. Expansion of surface water treatment capacity may be necessary if regional groundwater conditions deteriorate further.
Conclusion
Lodi's water supply can adequately support planned five-year growth through the Westside and Eastside visions, representing approximately 1,300 acre-feet per year in additional demand. The city's diversified portfolio of groundwater, surface water, and significant banked storage provides resilience for near-term development.
However, long-term sustainability requires proactive management of the critically overdrafted Eastern San Joaquin Subbasin and strategic planning for post-2047 surface water supplies. The ambitious South Study Area development should be contingent on achieving groundwater sustainability and securing additional surface water sources beyond the current WID contract.
Success in balancing growth aspirations with water supply sustainability will depend on effective implementation of regional groundwater management, expansion of recycled water use, and maintaining flexibility in development timing based on water supply security.
References
- City of Lodi Surface Water Treatment Facility - CEQAnet
- Is Lodi's Growth Plan realistic? - Lodi411
- Water Supply | Lodi, CA
- City of Lodi Surface Water Treatment Facility - CEQAnet
- Appendix C: Water Infrastructure and Supply Memorandum
- White Slough Water Pollution Control Facility Multi-Year Planning
- Chapter 3 - Growth Management and Infrastructure
- Water Purchase Agreement With Woodbridge Irrigation District
- Eastern San Joaquin Groundwater Authority Agenda
- About Us - Woodbridge Irrigation District
- Water Purchase Agreement with North San Joaquin Water Conservation District
- San Joaquin Valley – Eastern San Joaquin
- Eastern San Joaquin Groundwater Authority