Fluoride · California

Fluoride in California Drinking Water — 34 ZIPs Tested

EPA data analysis for fluoride in California drinking water systems

ZipCheckup tracks Fluoride in California drinking water: 34 ZIP codes with detected levels on record. 2 ZIP codes exceed the EPA limit (4.0 mg/L (MCL) / 2.0 mg/L (SMCL)). Fluoride carries a moderate health-risk designation.

34
ZIPs with Detections
2
ZIPs with Violations
0.1%
Violation Rate
4.0 mg/L (MCL) / 2.0 mg/L (SMCL)
EPA Limit
Moderate
Health Risk
Reverse Osmosis or Activated Alumina
Best Filter Method

Fluoride Contamination in California

ZipCheckup analyzed drinking water data across 2,630 ZIP codes in California for fluoride contamination. 34 ZIP codes have reported fluoride detections, and 2 have EPA violations on record.

The violation rate for fluoride in California is 0.1% of all ZIP codes — lower than the national average.

EPA Standard for Fluoride

The EPA maximum contaminant level (MCL) for fluoride is 4.0 mg/L (MCL) / 2.0 mg/L (SMCL), governed by the National Primary Drinking Water Regulations. Water systems that exceed this limit must take corrective action and notify consumers.

Worst ZIP Codes for Fluoride in California

These ZIP codes reported the highest fluoride levels in California based on CCR reports and EPA data:

Lowest Fluoride Levels in California

These ZIP codes had the lowest reported fluoride detections in California:

Health Effects of Fluoride

At levels above the EPA MCL of 4 mg/L, fluoride can cause skeletal fluorosis (bone pain, joint stiffness). The secondary standard of 2 mg/L is set to prevent dental fluorosis in children. At levels used in water fluoridation (0.7 mg/L), fluoride helps prevent tooth decay.

How to Remove Fluoride From Drinking Water

The most effective treatment for fluoride removal is Reverse Osmosis or Activated Alumina. Look for filters certified under NSF 58 standards.

Check Your ZIP Code

Use the ZipCheckup water quality search to see fluoride data for your specific water system in California.

Worst ZIP Codes for Fluoride in California

Ranked by highest fluoride detection level.

Rank ZIP Code City Level Detected EPA Limit Status
1 95005 Ben Lomond 485000 ppb 4000 ppb Exceeds
2 95006 Boulder Creek 485000 ppb 4000 ppb Exceeds
3 95007 Brookdale 485000 ppb 4000 ppb Exceeds
4 95017 Davenport 485000 ppb 4000 ppb Exceeds
5 93261 Richgrove 17500 ppb 4000 ppb Exceeds
6 92239 Desert Center 7800 ppb 4000 ppb Exceeds
7 93306 Bakersfield 6100 ppb 4000 ppb Exceeds
8 92365 Newberry Springs 5500 ppb 4000 ppb Exceeds
9 92860 Norco 2400 ppb 4000 ppb Within Limit
10 93243 Lebec 2300 ppb 4000 ppb Within Limit
11 92307 Apple Valley 1850 ppb 4000 ppb Within Limit
12 92384 Shoshone 1750 ppb 4000 ppb Within Limit
13 92389 Tecopa 1750 ppb 4000 ppb Within Limit
14 92236 Coachella 1700 ppb 4000 ppb Within Limit
15 92304 Amboy 1700 ppb 4000 ppb Within Limit
16 92332 Essex 1700 ppb 4000 ppb Within Limit
17 92338 Ludlow 1700 ppb 4000 ppb Within Limit
18 93225 Frazier Park 1700 ppb 4000 ppb Within Limit
19 92356 Lucerne Valley 1500 ppb 4000 ppb Within Limit
20 92277 Twentynine Palms 1460 ppb 4000 ppb Within Limit

Lowest Fluoride Levels in California

ZIP Code City Level Detected
93592 Trona 1070 ppb
93562 Trona 1070 ppb
91031 South Pasadena 1200 ppb
91030 South Pasadena 1200 ppb
91025 Sierra Madre 1200 ppb
91024 Sierra Madre 1200 ppb
91023 Mount Wilson 1200 ppb
91962 Pine Valley 1240 ppb
91948 Mount Laguna 1240 ppb
93266 Stratford 1300 ppb

Cities with Fluoride Data in California

27 cities in California have fluoride testing data available.

+ 7 more cities

California Water Quality Overview: See statewide water quality rankings on the California water quality page.
Learn more about Fluoride: Read the full guide on Fluoride in drinking water.
Home → Contaminants → Fluoride → California

How to cite this page

APA ZipCheckup. (2026). Fluoride in California Drinking Water — 34 ZIPs Tested. https://zipcheckup.com/contaminants/fluoride/california/
BibTeX 
@misc{zipcheckup-contaminants-fluoride-california,
  author = {{ZipCheckup}},
  title  = {{Fluoride in California Drinking Water — 34 ZIPs Tested}},
  year   = {2026},
  url    = {https://zipcheckup.com/contaminants/fluoride/california/}
}

Data as of July 2026.

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