# California Water Service Co-lake Hughes — San Jose, Ca, CA — Drinking Water Quality (2023)

> Contaminant levels for the California Water Service Co-lake Hughes — San Jose, Ca, CA public water system from its 2023 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/california-water-service-co-lake-hughes-san-jose-ca/2023
- JSON API: https://www.thewatermap.com/api/water/ca/california-water-service-co-lake-hughes-san-jose-ca/2023
- 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: 2023
- Contaminants measured: 25
- Contaminants with a federal limit: 8
- Contaminants at or above the federal limit: 0
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| HAA5 | Disinfection byproducts | 4.6 ug/L (Running annual avg) | Distribution System-Wide Highest Annual | No federal limit | Within the limit |
| TTHM | Disinfection byproducts | 22 ug/L (Running annual avg) | Distribution System-Wide Highest Annual | No federal limit | Within the limit |
| Fluoride | Inorganic chemicals | 0.64 mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| Nitrate | Inorganic chemicals | 4 mg/L (Average) | System-wide | 10 mg/L (MCL) | Within the limit |
| Arsenic | Metals | 4 ug/L (Average) | System-wide | No federal limit | Within the limit |
| Barium | Metals | Not detected mg/L (Average) | System-wide | 2 mg/L (MCL) | Within the limit |
| Calcium | Metals | 75 mg/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Chromium, Hexavalent | Metals | 0.41 ug/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Copper | Metals | Not detected mg/L (90th percentile) | At the tap | 1.3 mg/L (Action level) | None detected |
| Lead | Metals | Not detected ug/L (90th percentile) | At the tap | No federal limit | None detected |
| Lithium | Metals | Not detected ug/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Magnesium | Metals | 24 mg/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Potassium | Metals | 3.6 mg/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Selenium | Metals | Not detected ug/L (Average) | System-wide | No federal limit | Within the limit |
| Sodium | Metals | 32 mg/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Vanadium | Metals | 4.5 ug/L (Average) | Groundwater | 50 ug/L (NL) | Detected — no federal limit |
| Escherichia coli (E. coli) | Microbial | 0 (Maximum) | Monthly | No federal limit | None detected |
| Chlorine Free | Other | 1.1 mg/L (Average) | Distribution System-Wide | 4 mg/L (MCL) | Within the limit |
| Perfluoropentanoic acid | PFAS ("forever chemicals") | 1.2 ng/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| PFBA | PFAS ("forever chemicals") | 2.1 ng/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Alkalinity | Physical & aggregate | 280 mg/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Hardness | Physical & aggregate | 287 mg/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| pH | Physical & aggregate | 7.4 (Average) | System-wide | No federal limit | Detected — no federal limit |
| Gross Alpha | Radionuclides | 4.4 pCi/L (Average) | System-wide | 15 pCi/L (MCL) | Within the limit |
| Uranium | Radionuclides | 4.1 pCi/L (Average) | System-wide | 20 pCi/L (MCL) | Detected — no federal limit |

## What these contaminants are

- **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.
- **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.
- **Arsenic** — A naturally occurring element that also enters water from industry and agriculture. A known human carcinogen; long-term exposure is linked to skin, bladder, and lung cancer.
- **Barium** — A metal from erosion of natural deposits and industrial discharge. Long-term exposure above the federal limit can raise blood pressure.
- **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.
- **Magnesium** — A naturally occurring mineral that contributes to water hardness. Not federally regulated for health; affects scaling and taste.
- **Potassium** — A naturally occurring mineral from rock and soil. Not federally regulated for health.
- **Selenium** — A trace element from natural deposits and industrial discharge. Essential in tiny amounts, but long-term exposure above the federal limit can cause hair and fingernail loss and circulatory problems.
- **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.
- **Perfluoropentanoic acid** — Perfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **PFBA** — Perfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment and the human body.
- **Alkalinity** — A measure of the water's capacity to neutralize acids. Not federally regulated for health; relevant to corrosion control and treatment.
- **Hardness** — A measure of dissolved calcium and magnesium minerals. Not federally regulated for health; affects scaling, soap use, and taste.
- **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.
- **Gross Alpha** — Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases cancer risk.
- **Uranium** — A naturally occurring radioactive metal from erosion of natural deposits. Long-term exposure above the federal limit can damage the kidneys and increase 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 2026-06-04 from thewatermap.com._