Data & Methodology — Solano County

Full contaminant data, sample history, and sourcing for Solano County. For readers who want to go beyond the summary.

Contaminant Data — All Analytes

313 well testing events on record, covering 25 analytes. Data spans 1946 to 2022.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. CA Avg
Manganese 63 1974–2022 35%
80% of limit ↓ 74% below
Arsenic 61 1974–2022 95%
30% of limit ↓ 23% below
Iron 81 1950–2022 69%
3% of limit ↓ 97% below
Chloride 261 1946–2022 100%
14% of limit ↓ 55% below
Nitrate 82 1958–2022 98%
16% of limit ↓ 32% below
PFOS municipal 86 2022–2025 3%
250% of limit ~ typical
PFOA municipal 86 2022–2025 2%
121% of limit ↓ 27% below
Sulfate 173 1946–2022 100%
16% of limit ↓ 23% below
PFHxS municipal 86 2022–2025 5%
92% of limit ↑ 63% above
Radon 1 2012 100%
90% of limit ~ typical
HFPO-DA (GenX) municipal 86 2022–2025 0%
— —
Nitrite 19 2005–2022 26%
0% of limit ↓ 76% below
Fluoride 140 1951–2022 100%
8% of limit ~ typical
Perchlorate 4 2005–2022 75%
6% of limit ~ typical
Uranium 19 2005–2022 100%
6% of limit ~ typical
PFNA municipal 86 2022–2025 0%
— —
Boron 4 2005–2022 100%
10% of limit ↓ 40% below
Chromium (total) 4 2005–2022 25%
10% of limit ↑ 289% above
1,2,3-Trichloropropane 7 2005–2022 0%
— —
Lead 25 1974–2022 48%
7% of limit ↓ 30% below
Tds 4 2005–2022 100%
— ↑ 137% above
Sodium 248 1946–2022 100%
— ↓ 23% below
Hardness 252 1946–2022 100%
— ~ typical
PFBS municipal 86 2022–2025 5%
— ~ typical
pH 256 1946–2022 100%
— ~ typical

Distribution shows the share of samples in each concentration band relative to the EPA Maximum Contaminant Level (MCL): Low = below half the MCL, Moderate = between half and the MCL, High = above the MCL. Analytes without an MCL (e.g. sodium, pH) show — in the limit columns. State average is based on county median values across CA.

Compare your result with Solano County

Of the 61 arsenic tests on record for Solano County (1974–2022), 5% found none, and half were below 3 µg/L.

Of the 261 chloride tests on record for Solano County (1946–2022), 0% found none, and half were below 34 mg/L.

Of the 140 fluoride tests on record for Solano County (1951–2022), 0% found none, and half were below 300 µg/L.

Of the 81 iron tests on record for Solano County (1950–2022), 31% found none, and half were below 10 µg/L.

Of the 25 lead tests on record for Solano County (1974–2022), 52% found none.

Of the 63 manganese tests on record for Solano County (1974–2022), 65% found none.

Of the 82 nitrate tests on record for Solano County (1958–2022), 2% found none, and half were below 1.6 mg/L.

Of the 173 sulfate tests on record for Solano County (1946–2022), 0% found none, and half were below 39 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 63 samples
  • Arsenic 61 samples
  • Iron 81 samples
  • Chloride 261 samples
  • Nitrate 82 samples
  • PFOS 86 samples
  • PFOA 86 samples
  • Sulfate 173 samples
  • PFHxS 86 samples
  • HFPO-DA (GenX) 86 samples
  • Nitrite 19 samples
  • Fluoride 140 samples
  • Uranium 19 samples
  • PFNA 86 samples
  • Lead 25 samples
  • Sodium 248 samples
  • Hardness 252 samples
  • PFBS 86 samples
  • pH 256 samples

Limited data (<15 samples) — interpret with caution

  • Radon 1 sample
  • Perchlorate 4 samples
  • Boron 4 samples
  • Chromium (total) 4 samples
  • 1,2,3-Trichloropropane 7 samples
  • Tds 4 samples

Public vs. Private Water in Solano County

63 Active public water systems
473,083 Residents on public water
5% Households on private wells

Public water systems in Solano County are regulated by the EPA and must test and report contaminant levels. Private well owners are responsible for their own testing — there is no routine monitoring of private wells by any government agency.

CDC Health Outcome Correlations

Where contaminants detected in Solano County have established associations with specific health outcomes, we cross-reference CDC PLACES county-level prevalence data. This is a contextual signal, not a causal claim.

Contaminant Associated Condition Solano County Prevalence CA Average Source Year
Arsenic Cancer prevalence 6.0% 6.2% 2020
Arsenic Kidney disease rate 2.6% 3.0% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Solano County CDC PLACES data →

Data Sources

This report aggregates data from the following public databases:

Methodology

Raw records are downloaded from the Water Quality Portal and normalized to µg/L (ppb). Records are deduplicated by sample ID and date, and certified outliers are excluded. Analyte names are mapped to EPA canonical forms. Detection rates, distribution bands, and MCL comparisons are computed from the normalized dataset.

Distribution bands use the EPA Maximum Contaminant Level as the threshold: concentrations below 50% of the MCL are classed as Low, between 50% and 100% as Moderate, and above 100% as High. For analytes without an MCL (sodium, hardness, pH), distribution is not computed.

State comparison uses the median of county median values across all counties in CA with at least one sample for that analyte.

Last updated: 2026-09-10

Full methodology →