Hollister, California Water Quality Report
Water quality data for 29 water systems serving 53,923 people.
Water Source
Detected Contaminants
Recommended Water Filters
Based on the contaminants detected in your water supply, these filtration systems are recommended:
Reverse Osmosis (RO)
Reverse osmosis systems remove up to 99% of PFAS compounds. Recommended for homes with detected PFAS.
Up to 99% PFAS removal
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Compliance & Violations
Active Violations (21)
4G
Oct 17, 2024
2E
Oct 17, 2024
4G
Oct 17, 2024
2E
Oct 17, 2024
2E
Oct 17, 2024
4G
Oct 17, 2024
34
Jul 4, 2024
52
Jul 1, 2024
52
Jan 1, 2024
71
Jul 1, 2023
52
Jul 1, 2023
52
Sep 9, 2022
52
Sep 9, 2022
52
Jul 1, 2022
52
Jul 1, 2022
52
Jan 1, 2022
52
Jan 1, 2022
52
Jul 1, 2021
52
Jul 1, 2021
52
Jan 1, 2021
52
Jan 1, 2021
Resolved Violations (479)
3A
May 1, 2025 — May 31, 2025
3A
Jun 1, 2024 — Jun 30, 2024
3A
Jun 1, 2024 — Jun 30, 2024
27
Apr 1, 2024 — Jun 30, 2024
75
Apr 1, 2024
+ 474 more resolved violations
Frequently Asked Questions
Is Hollister tap water safe to drink?
Hollister's water has 1 contaminant detected above EPA limits. While the water is treated, residents may want to consider additional filtration.
What contaminants are in Hollister tap water?
2 contaminants have been detected in Hollister's water supply across 29 water systems. See the full contaminant table above for details.
How can I improve my water quality in Hollister?
Install a water filter rated for the specific contaminants found in Hollister's water. See our filter recommendations above. You can also request your utility's Consumer Confidence Report for the most current test results.
Does Hollister have any water quality violations?
Yes, Hollister currently has 39 active violations. See the violations section above for details.