# Santa Rosa, CA — Drinking Water Quality (2024)

> Contaminant levels for the Santa Rosa, CA public water system from its 2024 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/santa-rosa/2024
- JSON API: https://www.thewatermap.com/api/water/ca/santa-rosa/2024
- Source: the utility's annual Consumer Confidence Report (CCR)
- Verification: transcribed by a model, cross-checked by a second model, approved before publishing
- Reporting year: 2024
- Contaminants measured: 30
- Contaminants with a federal limit: 22
- Contaminants at or above the federal limit: 4
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| Chlorine | Disinfectants | 0.18–1.74 mg/L (Range) | Santa Rosa | No federal limit | Detected — no federal limit |
| HAA5 | Disinfection byproducts | 3.7–25.9 ug/L (Range) | Sonoma Water | 60 ug/L (MCL) | Within the limit |
| TTHM | Disinfection byproducts | 22.1–32.9 ug/L (Range) | Santa Rosa | 80 ug/L (MCL) | Within the limit |
| Chloride | Inorganic chemicals | 16.4–21.7 mg/L (Range) | Santa Rosa | 500 mg/L (MCL) | Within the limit |
| Fluoride | Inorganic chemicals | 0.16–0.18 mg/L (Range) | Santa Rosa | 1 mg/L (Public health goal) | Within the limit |
| Nitrate | Inorganic chemicals | Not detected mg/L (Reported level) | Sonoma Water | 10 mg/L (Public health goal) | None detected |
| Sulfate | Inorganic chemicals | 13–15 mg/L (Range) | Sonoma Water | 0.5 mg/L (MCL) | At or above the limit |
| Calcium | Metals | 26.7–27.9 mg/L (Range) | Santa Rosa | No federal limit | Detected — no federal limit |
| Chromium, Hexavalent | Metals | 0.29–0.47 ug/L (Range) | Sonoma Water | 0.02 ug/L (Public health goal) | At or above the limit |
| Copper | Metals | 0.02–0.22 mg/L (Range) | Santa Rosa | 0.3 mg/L (Public health goal) | Within the limit |
| Lead | Metals | 0–11.6 ug/L (Range) | Santa Rosa | 0.2 ug/L (Public health goal) | At or above the limit |
| Lithium | Metals | 93 ug/L (Reported level) | Reporting Value | No federal limit | Detected — no federal limit |
| Manganese | Metals | 0–8.3 ug/L (Range) | Santa Rosa | 20 ug/L (MCL) | Within the limit |
| Sodium | Metals | 47–50.2 mg/L (Range) | Santa Rosa | No federal limit | Detected — no federal limit |
| Escherichia coli (E. coli) | Microbial | 0 (Reported level) | Santa Rosa | 0 (Public health goal) | None detected |
| Total Coliform | Microbial | 0 (Reported level) | Santa Rosa | 0 (Public health goal) | None detected |
| Hexafluoropropylene oxide dimer acid | PFAS ("forever chemicals") | Not detected ng/L (Range) | Range Detected | 10 ng/L (MCL) | None detected |
| Perfluorobutanesulfonic acid | PFAS ("forever chemicals") | Not detected ng/L (Reported level) | Reporting Value | 500 ng/L (MCLG) | None detected |
| Perfluorohexanesulfonic acid | PFAS ("forever chemicals") | Not detected ng/L (Reported level) | Reporting Value | 3 ng/L (MCLG) | None detected |
| PFOA | PFAS ("forever chemicals") | Not detected ng/L (Range) | Range Detected | 5.1 ng/L (MCLG) | None detected |
| PFOS | PFAS ("forever chemicals") | Not detected ng/L (Range) | Range Detected | 10 ng/L (MCL) | None detected |
| Alkalinity | Physical & aggregate | 230–240 mg/L (Range) | Santa Rosa | No federal limit | Detected — no federal limit |
| Color | Physical & aggregate | 0–6 (Range) | Sonoma Water | 15 (MCL) | Within the limit |
| Hardness | Physical & aggregate | 137–142 mg/L (Range) | Santa Rosa | No federal limit | Detected — no federal limit |
| Odor | Physical & aggregate | Not detected (Range) | Santa Rosa | 1 (MCL) | None detected |
| pH | Physical & aggregate | 7.5–8.6 (Range) | Santa Rosa | No federal limit | Detected — no federal limit |
| Specific Conductance | Physical & aggregate | 450–490 (Range) | Santa Rosa | 1600 (MCL) | Within the limit |
| Temperature | Physical & aggregate | 10.6–28.8 (Range) | Santa Rosa | No federal limit | Detected — no federal limit |
| Total Dissolved Solids | Physical & aggregate | 340–360 mg/L (Range) | Santa Rosa | 1000 mg/L (MCL) | Within the limit |
| Radon | Radionuclides | 445–455 pCi/L (Range) | Santa Rosa | 100 pCi/L (MCL) | At or above the limit |

## What these contaminants are

- **Chlorine** — A disinfectant added to drinking water to kill bacteria and viruses. Effective and necessary, but high residual levels can cause taste and odor issues; the EPA caps the residual disinfectant level.
- **HAA5** — Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. Long-term exposure above the federal limit is associated with an increased cancer risk.
- **TTHM** — Total trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. Long-term exposure above the federal limit is linked to liver, kidney, and central-nervous-system effects and increased cancer risk.
- **Chloride** — A naturally occurring salt compound. Regulated only as a secondary (cosmetic) standard; high levels cause a salty taste and can corrode pipes.
- **Fluoride** — A mineral often added to drinking water to help prevent tooth decay. Beneficial at low levels, but long-term exposure above the federal limit can cause bone disease and tooth mottling.
- **Nitrate** — A compound from fertilizer runoff, septic systems, and erosion of natural deposits. Levels above the federal limit can cause 'blue baby syndrome,' a serious oxygen-transport condition in infants.
- **Sulfate** — A naturally occurring mineral from rock and soil. No health-based federal limit; high levels can have a laxative effect and a bitter taste.
- **Calcium** — A naturally occurring mineral that contributes to water hardness. Not federally regulated for health; affects scaling and taste.
- **Chromium, Hexavalent** — Hexavalent chromium ('chromium-6') — the more toxic form of chromium. A known carcinogen by inhalation; regulated nationally only within the total-chromium limit, with stricter limits in some states.
- **Copper** — A metal that enters water from corroding household plumbing. Short-term exposure causes stomach distress; long-term exposure can damage the liver and kidneys.
- **Lead** — A toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. There is no safe level of lead; it harms brain development in children and raises blood pressure in adults. The EPA sets an action level, not a health goal above zero.
- **Lithium** — A naturally occurring element found in some groundwater. No enforceable federal limit; on the EPA contaminant candidate list for further study.
- **Manganese** — A naturally occurring metal from soil and rock. No enforceable federal limit; high levels stain fixtures and laundry and can affect taste, with a health advisory for infants.
- **Sodium** — A naturally occurring salt component. Not federally regulated for health; relevant for people on sodium-restricted diets.
- **Escherichia coli (E. coli)** — Escherichia coli — bacteria found in the gut of humans and animals. Its presence in drinking water indicates fecal contamination and a real risk of waterborne illness.
- **Total Coliform** — A group of bacteria used as an indicator of overall water-system sanitation. Coliforms themselves are usually harmless, but their presence signals that disease-causing organisms could enter the system.
- **Hexafluoropropylene oxide dimer acid** — HFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **Perfluorobutanesulfonic acid** — Perfluorobutanesulfonic acid, a shorter-chain PFAS 'forever chemical.' Has no standalone limit but is part of the EPA PFAS Hazard Index that limits PFAS in combination.
- **Perfluorohexanesulfonic acid** — Perfluorohexanesulfonic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **PFOA** — Perfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. Linked to cancer, liver damage, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
- **PFOS** — Perfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
- **Alkalinity** — A measure of the water's capacity to neutralize acids. Not federally regulated for health; relevant to corrosion control and treatment.
- **Color** — A measure of visible tint in the water. Regulated only as a secondary (cosmetic) standard.
- **Hardness** — A measure of dissolved calcium and magnesium minerals. Not federally regulated for health; affects scaling, soap use, and taste.
- **Odor** — A measure of detectable smell in the water. Regulated only as a secondary (cosmetic) standard.
- **pH** — A measure of how acidic or basic the water is. Regulated only as a secondary standard; very low or high pH can corrode pipes or affect taste.
- **Specific Conductance** — A measure of how well water conducts electricity, which tracks dissolved mineral content. Not federally regulated for health; used as a proxy for total dissolved solids.
- **Temperature** — The measured temperature of the water sample. Not regulated for health; warmer water can affect disinfection and microbial growth.
- **Total Dissolved Solids** — Total dissolved solids — the combined content of all dissolved minerals and salts. Regulated only as a secondary (cosmetic) standard; high levels affect taste and hardness.
- **Radon** — A naturally occurring radioactive gas that can dissolve into groundwater. No enforceable federal limit in drinking water yet; inhalation of released radon raises lung-cancer risk.

## How to read this

- A water-quality report covers an entire service area, not a single address.
- 'Federal limit' is the EPA standard (MCL, action level, treatment technique, etc.) that the measured level is compared against.
- 'At or above the federal limit' means the utility's own reported figure met or exceeded that standard.

_Figures are the utility's own published numbers. Generated 2026-05-25 from thewatermap.com._