City of Calistoga water quality report, rewritten
- Serves
- 5,610
- Connections
- 2,229
- Water source
- Surface water
- Based in
- Calistoga, CA
- County
- Napa
- Owner
- Local government
The ZIP code it serves
PWSID CA28100022026 edition · EPA data
Read this first
- PFOS (above the health goal) was found in one of 8 samples, highest 12.2 ppt. Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
- PFOA (above the health goal) was found in one of 8 samples, highest 6.4 ppt. Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
8 health-based violations since 2016. Details are below.
What handles itWhat was found
Highlighted: above the health goal, or EPA’s health benchmark where there is no goal. Circled: above the legal limit in at least one sample, or the action level. Every scale puts that line at its middle.
PFOS (above the health goal)
Comes from the source
12.2 (above the legal limit in at least one sample)ppt
Highest of 8 samples; found in one
Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
What handles it
- NSF/ANSI 53Look for: PFOS ReductionSame claim, other certifiers’ wording: Total PFAS Reduction; Perfluorooctane Sulfonate (PFOS)
- NSF/ANSI 58Look for: Perfluorooctane Sulfonate (PFOS)
NSF’s PFAS claims are tested to below 20 ppt. EPA’s limit is 4.0 ppt, and EPA says no certification yet shows a filter reaching its levels.
EPA UCMR 5, samples taken on June 4, 2024. Each blue tick is one sample where it was found.
PFOA (above the health goal)
Comes from the source
6.4 (above the legal limit in at least one sample)ppt
Highest of 8 samples; found in one
Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
What handles it
- NSF/ANSI 53Look for: PFOA ReductionSame claim, other certifiers’ wording: Total PFAS Reduction; Perfluorooctanoic Acid (PFOA)
- NSF/ANSI 58Look for: Perfluorooctanoic Acid (PFOA)
NSF’s PFAS claims are tested to below 20 ppt. EPA’s limit is 4.0 ppt, and EPA says no certification yet shows a filter reaching its levels.
EPA UCMR 5, samples taken on June 4, 2024. Each blue tick is one sample where it was found.
Also found, with no federal limit
EPA measured these PFAS to learn how often they occur. None has a legal limit or a health goal yet.
| Compound | Highest sample | Found in | Certification claim |
|---|---|---|---|
| PFPeA | 4.2 ppt | 1 of 8 | None covers it |
| PFHxA | 3.2 ppt | 1 of 8 | None covers it |
Tested and not found
Below EPA’s minimum reporting level in every sample taken from April 10, 2024 to April 8, 2025. Not found means not measured above that level, which is not the same as zero.
All 27 compounds tested and not found
- 11Cl-PF3OUdS
- 4:2 FTS
- 6:2 FTS
- 8:2 FTS
- 9Cl-PF3ONS
- ADONA
- HFPO-DA (GenX)
- Lead
- Lithium
- NEtFOSAA
- NFDHA
- NMeFOSAA
- PFBA
- PFBS
- PFDA
- PFDoA
- PFEESA
- PFHpA
- PFHpS
- PFHxS
- PFMBA
- PFMPA
- PFNA
- PFPeS
- PFTA
- PFTrDA
- PFUnA
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | July 1, 2023 to Sept. 30, 2023 | 67.3 UG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | April 1, 2023 to June 30, 2023 | 74.4 UG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2023 to March 31, 2023 | 72 UG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | April 1, 2018 to June 30, 2018 | 0.069 MG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2018 to March 31, 2018 | 0.062 MG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Oct. 1, 2017 to Dec. 31, 2017 | 0.062 MG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | July 1, 2017 to Sept. 30, 2017 | 0.061 MG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Oct. 1, 2016 to Dec. 31, 2016 | 0.064 MG/L | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown. | ||||
What handles it
A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”
- NSF/ANSI 53
Claims: PFOS Reduction, PFOA Reduction
For: PFOS, PFOA
- NSF/ANSI 58
Claims: Perfluorooctane Sulfonate (PFOS), Perfluorooctanoic Acid (PFOA)
For: PFOS, PFOA
At the tap, or for the whole house?
These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. How whole-house systems compare.
Filters with those claims on a certifier’s listing
TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money
Under-sink reverse osmosis
Certified for: PFOS, PFOA
Countertop reverse osmosis
Certified for: PFOS, PFOA
Whole house
Certified for: PFOS, PFOA
What this report cannot tell you
- Levels of everything else. Federal bulk data carries results for PFAS, lithium, lead and copper, and violations for the rest. Nitrate, arsenic, disinfection byproducts and other levels are in City of Calistoga’s own annual report, which it must send you every year.
- Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
- Anything after the latest data. SDWIS data is from 2026 Q2; UCMR 5 samples are from April 10, 2024 to April 8, 2025.
What to do next
Read up on the 2 marked results
What each one does to health, where it comes from, and the certification claim that addresses it.
Start with PFOSGet the utility’s own report
City of Calistoga must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.
How to read itTest your own tap for lead
Your service line, solder and fixtures decide the lead at your faucet, not the utility’s average.
Lead in your water: what to doCompare certified filters
What the filters certified for these results cost over five years, cartridges included.
Compare five-year costs
Other California utilities
- Los Angeles - City, Dept. of Water & Power3.9 million
- East Bay MUD1.4 million
- City of San Diego1.4 million
- San Jose Water1 million
- SFPUC City Distribution Division848,019
- Eastern Municipal WD666,581
- City of Fresno545,716
- City of Sacramento Main527,979
- Long Beach Utilities Department466,772
- Irvine Ranch Water District444,800
- City of Anaheim348,593
- Alameda County Water District344,000
Sources
- EPA UCMR 5 occurrence data, file of Aug. 27, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q2
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.