If you farm in North County San Diego, your irrigation water likely comes from Rainbow Municipal Water District (RMWD) or the Fallbrook Public Utility District (FPUD). Both agencies recently released their 2024 Consumer Confidence Reports, confirming that local drinking and irrigation water continues to meet all state and federal safety standards. Here’s what matters most for growers:

🌿 Rainbow Municipal Water District (RMWD)

• Source: 100% imported Colorado River and State Water Project water, treated at the Skinner Treatment Plant
• Water quality: All regulated contaminants were well below limits
• Key takeaway: Average hardness ~242 mg/L (hard water), which can contribute to scale in drip systems and filters
• PFAS: Non-detect; only trace lithium detected, well below any action level
• Summary: Safe, reliable water, but expect high mineral content that may affect irrigation equipment and soil over time

🌱 Fallbrook Public Utility District (FPUD)

• Source: Blended supply of imported water and local groundwater (reverse osmosis + UV treatment)
• Water quality: No state or federal violations
• 2024 note: A brief September power outage caused a short-term boil water notice; service was quickly restored
• Irrigation benefit: The groundwater blend can slightly reduce salinity
• Summary: Clean, well-treated water with generally stable quality

🌾 What Growers Should Watch For

• Manage scale buildup from hard water in drip, micro, and fertigation systems
• Monitor EC, TDS, and sodium for salt-sensitive crops
• Expect minor seasonal variation in FPUD’s blended supply
• Keep contact information current for emergency water advisories

🚜 Free Irrigation Efficiency Support Available

Growers in the Rainbow and Fallbrook service areas can access free irrigation efficiency evaluations through Mission Resource Conservation District’s WETA Program (funded by CA Department of Food & Agriculture). Services include:

• Irrigation system efficiency evaluations 
• Water and soil tests
• Expert support
• Pump efficiency testing for well users

Eligible growers may also receive help applying for NRCS cost-share funding for system upgrades.

Why this matters: With hard, mineral-rich water and rising water costs, improving irrigation efficiency helps protect crops, extend equipment life, and reduce unnecessary pumping and energy use.

Learn More

• Rainbow MWD Water Quality
• FPUD Water Quality
• WETA Program

Sources:

Fallbrook Public Utility District. 2025 Water Quality Report (Consumer Confidence Report). 2025. https://www.fpud.com/files/e382a2f70/Water+Quality+Report+2025++Web+Final.pdf

Rainbow Municipal Water District. 2024 Consumer Confidence Report. 2024. https://www.rainbowmwd.ca.gov/files/7c30a3bb2/RMWD+CCR+2024+Report+WEB+Final+.pdf