2025 PUBLIC HEALTH GOALS REPORT
Council Water Committee
Item 25-0897
August 14, 2025
Summary
Public Health Goals report is required every 3 years
Reports on Water Quality pertain to:
State Public Health Goals
Federal Maximum Contaminant Levels
Background
Public Health Goals are non-enforceable goals established by Cal-EPA’s Office of Environmental Health Hazard Assessment Compares actual water quality to State Public Health Goals Discusses what actions are taken to reduce water constituents to below Public Health Goals
How are Contaminants Measured ?
Milligrams per liter – mg/l
1 milligram per liter is the same as 1 part per million.
Micrograms per liter – ug/l
1 microgram per liter is 1 part per billion.
Picocuries per liter – pCi/L
A picocurie is 1 trillionth of a curie, which quantifies radioactivity.
Report Findings
Water constituents that exceeded a Public Health Goal (PHG) or Maximum Contaminant Level Goal (MCLG) Arsenic (PHG 0.004 ug/L, MCL 10 ug/L) 2 – 6.4 ug/L
Bromate (PHG 1 ug/L, MCL 10 ug/L) Average 6.1 ug/L
Radionuclides
Gross Alpha (MCLG 0 pCi/L, MCL 15pCi/L)Ave4.17pCi/L
Radium-228 (PHG .019 pCi/L, MCL 5 pCi/L) Ave 0.5 pCi/L Uranium (PHG 0.43 pCi/L, MCL 20 pCi/L) Ave 3.93pCi/L
Total Coliforms (MCLG 0 Samples, MCL < 5%) 145-186 Samples pass each month.
Arsenic
Occurs naturally in many rocks and sediments
Human activities such as mining, industry, and use in pesticide can lead to water contamination Is toxic at low levels
Maximum Contaminate Level in Water Supplies is 10 ug/L Impacts groundwater
Bromate
Occurs when surface water with Bromide is treated with Ozone.
Only occurs in City’s Surface Water Supply at the Delta Water Treatment Plant Maximum Contaminate Level in Water Supplies is 10 ug/L
Radionuclides
Best Available Technologies and Treatment CostsIon Exchange Unit – Removes Arsenic and PFAS Project - Well Rehabilitation
Location – Ernie Shropshire Park
Project Cost - $4.8M
Project Completion - 2024
Capacity – 1,500 gpm
Best Available Technologies and Treatment CostsGranular Activated Carbon Pressure ContactorsRemoves Dissolved Organic Compounds Image Source: www.westechwater.com/products/granular-activated-carbon-contactors
Best Available Technologies and Treatment CostsReverse Osmosis Treatment Image Source: https://www.marlo-inc.com/news/1000-gpm-reverse-osmosis-ro-system
Best Available Technologies and Treatment Costs
Arsenic – Ion Exchange Treatment Units
Cost would be about $248/year per connection
Bromate – Granular Activated Carbon Treatment
Cost would be about $174/year per connection
Radionuclides - Reverse Osmosis
Cost would be about $1,510/year per connection
Total Coliforms – Already Utilizing BAT
Maintain chlorine residuals
Monitor treatment processes
Positive System Pressure
Public Notice
Report is to be approved by Council at a public hearing Public Hearing will be noticed to the Stockton Record
Public Health Goals Report is available on the City website at www.stocktonca.gov/WaterQuality
Recommendation
Recommend to the City Council to Approve the 2025 Public Health Goals Report