- American States Water Companies
- California - Department of Water Resources
- El Toro Water District
- Los Angeles Department of Water & Power
- Metro Water District
- Mouton Niguel Water District
- Irvine Ranch Water District
- Orange County Water District
- Santa Clarita Water District
- The Metropolitan Water District of Southern California (MWD)
- The Water Replenishment District of Southern California (WRD)
- Water Quality Association (WQA)
- Western Municipal Water District (WMW)
- Association of California Water Agencies (ACWA)
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