Orange County’s Water Outlook: What the Latest Plan Shows

Sarina Sriboonlue, Principal Engineer, Municipal Water District of Orange County
May 20, 2026

Every five years, California water agencies must prepare an Urban Water Management Plan (UWMP), a long‑range planning document required by state law. UWMPs evaluate how much water a region will need over the next 20–25 years and whether supplies are expected to meet that demand under normal and dry conditions.

The Municipal Water District of Orange County (MWDOC) does not operate pipelines or treatment plants; instead, it purchases imported water from The Metropolitan Water District of Southern California (Metropolitan), supports local agencies in planning and emergency preparedness, and leads countywide water efficiency and education programs. The 2025 UWMP outlines how these combined efforts support long‑term reliability for the region.

1. What Water Use Looks Like Now

Even with a growing population, Orange County’s total water use has continued to decline since the early 2000s. A major reason for this is decades of increased efficiency. Efficient appliances, smart yard irrigation, new landscaping norms, and public awareness campaigns have all made a measurable difference.

A pie chart graph that illustrates MWDOC's 2024-2025 Fiscal Year Water Usage broken down into various slices: Untreated Imported at 7%, Surface Water at 2%, Non-OC Basin Groundwater at 4%, Recycled Non Potable at 12%, Treated Imported at 24% and Orange County Groundwater Basin at 51%. 21% of that OC Groundwater Basin comes from GWRS and 30% of it comes from Native Recharge.
MWDOC Service Area Water Supply Portfolio – Fiscal Year 2024-25                                                                           GWRS = Groundwater Replenishment System

 

2. How Water Use is Expected to Change

OC’s long-term water demand is forecast to remain flat over the next two decades. Efficiency continues to improve and is expected to offset demand pressures from modest population growth.

3. Where Our Water Comes From

Orange County’s water supply comes from both local and imported sources. About two‑thirds is local, mainly groundwater from the Orange County Groundwater Basin, along with recycled water and surface water from reservoirs like Irvine Lake. The rest is imported through regional pipelines from the Colorado River and Northern California.

4. Is Our Water Supply Reliable?

MWDOC projects reliable water supplies through 2050. The Orange County Groundwater Basin remains a stable local source, and recycled water continues to expand. New local supplies, including the upcoming Doheny Ocean Desalination Project, will further strengthen reliability. Imported water remains available through Metropolitan, which maintains strong storage reserves and operates diversified programs that allow it to move and supplement supplies across Southern California when needed.

5. How We Prepare for Water Shortages

MWDOC maintains a Water Shortage Contingency Plan that outlines how the region would respond if water supplies became limited due to drought, emergencies, or disruptions in imported water deliveries. The plan outlines clear steps, such as increasing conservation and coordinating with local water providers, to help the region reduce demand in an organized way and protect essential water needs.

Community members can learn more by reading MWDOC’s 2025 Urban Water Management Plan at www.mwdoc.com/your-water/urban-water-management-plan/.