October 21, 2025 Item # 7
City Council
Public Hearing: 2025 Report on Water
Quality Relative to Public Health Goals
1852
THE MISSION CIT
John Ramirez, Director, Water and Sewer Utilities
Agenda Item # 7, (25-910)
October 21, 2025
City of
Santa Clara
The Conser Di Whuth Possible
Agenda
• Public Health Regulations
• Public Health Goal
• Background
• Monitoring and Testing Program
• Findings
• Report Conclusions
Recommendation
2 POST MEETING MATERIAL
1 Item 7 10/21/2025
City of
Santa Clara
Public Health Goal Regulations
• The City is mandated by the Safe Drinking Water Act to hold a Public Hearing every 3 years to present information on:
- Public Health Goals (PHGs)
- Background on water quality
- Findings from ongoing testing
- Monitoring and testing programs
- PHG report conclusion
- Recommendations, if any, for additional treatment
City of
Santa Clara
The Corker of hot Possibly
Public Health Goals
• What is a PHG:
- Level of a contaminant in water that does not pose any significant risk to health
- Are not regulatory standards and are non-enforceable
- Serve as a guideline for evaluating water quality
- Protect public health by reporting detected contaminants 4 2
Item 7 10/21/2025
City of
Santa Clara
Background
• California Office of Environmental Health Hazard Assessment (OEHHA) establishes PHGs for contaminants, based on:
'- Scientific data from laboratory studies
- Results which provide a contaminant's adverse health effects - Levels that do not cause significant health effects
- OEHHA established 102 PHGs for containments in water
5 City of
Santa Clara
The Conter of Whit's Possible
Monitoring and Testing Program
• The Water Utility's State Approved Water Quality Monitoring Plan
- 5-year state approved water quality monitoring plan
- 34 approved sample stations located throughout the City - 160 constituents tested weekly, monthly, quarterly, and annually
3 Item 7 10/21/2025
City of
Santa Clara
Try Center of Whats Poosible
Findings
• Contaminants that exceeded their PHG levels in Santa Clara - Arsenic: naturally occurring in groundwater as a result of decay and erosion of natural deposits
- Hexavalent Chromium: introduced through the leaching
of natural deposits
- Perchlorate: introduced through industrial processes or from natural sources
City of
Santa Clara
The Conter of Wiste Possible
Arsenic
Arsenic is naturally occurring in most rocks and ends up in groundwater because of decay and erosion of natural deposits Public Health Goal 0.004 parts per billion
Detection Level for Reporting 2 parts per billion
Maximum Contaminant Level 10 parts per billion
Range of Results in Santa Clara ND - 2.2 parts per billion ND = Non-detect
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Item 7 10/21/2025
City of
Santa Clara
The Center of Whaty Footible
Hexavalent Chromium
Hexavalent Chromium can be introduced into water
sources through the leaching of natural deposits
Public Health Goal 0.02 parts per billion
Detection Level for Reporting 0.1 parts per billion
Maximum Contaminant Level 10 parts per billion
Range of Results in Santa Clara ND - 4.3 parts per billion ND = Non-detect
9 City of
Santa Clara
The Conter of Whats Positie
Perchlorate
Perchlorate can be introduced into a water source through industrial processes or from natural sources
Public Health Goal 1 parts per billion
Detection Level for Reporting 1 parts per billion*
Maximum Contaminant Level 6 parts per billion
Range of Results in Santa Clara ND - 1.3 parts per billion ND = Non-detect
*Perchlorate detection level for reporting was changed from 2 ppb to 1ppb in 2024 10 5
Item 7 10/21/2025
City of
Santa Clara
The Cunter of Whats Possibis
Report Conclusions
• The Water Utility continues to regularly monitor drinking water quality and is not proposing to change its current operations based on the information provided
- The City's drinking water meets all state and federal regulatory requirements per the Safe Drinking Water Act - Concentrations were very low; well below the enforceable Maximum Contaminant Levels
11 City of
Santa Clara
The Center of Whats Possible
Recommendation
• That Council accept
the 2025 PHG Report on
the City's Water Quality
Relative to Public Health
Goals
12 Item 7 10/21/2025
City of
Santa Clara
TEd Center of Whath Possible
Questions
13 7