# Pasadena, CA — Drinking Water Quality (2023)

> Contaminant levels for the Pasadena, CA public water system from its 2023 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/pasadena/2023
- JSON API: https://www.thewatermap.com/api/water/ca/pasadena/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: 65
- Contaminants with a federal limit: 57
- Contaminants at or above the federal limit: 2
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| Chlorine | Disinfectants | 1.4 mg/L (Average) | Pasadena Water System Highest | 4 mg/L (MRDL) | Within the limit |
| HAA5 | Disinfection byproducts | 19 ug/L (Average) | Pasadena Water System Highest | 60 ug/L (MCL) | Within the limit |
| Perchlorate | Disinfection byproducts | 1.3 ug/L (Average) | Pasadena Sources | 6 ug/L (MCL) | Within the limit |
| TTHM | Disinfection byproducts | 46 ug/L (Average) | Pasadena Water System Highest | 80 ug/L (MCL) | Within the limit |
| Chloride | Inorganic chemicals | 53 mg/L (Average) | Pasadena Sources | 500 mg/L (MCL) | Within the limit |
| Fluoride | Inorganic chemicals | 0.8 mg/L (Average) | Pasadena Sources | 2 mg/L (MCL) | Within the limit |
| Nitrate | Inorganic chemicals | 4.6 mg/L (Average) | Pasadena Sources | 10 mg/L (MCL) | Within the limit |
| Sulfate | Inorganic chemicals | 102 mg/L (Average) | Pasadena Sources | 500 mg/L (MCL) | Within the limit |
| Aluminum | Metals | 115 ug/L (Average) | MWD Weymouth Plant | 1000 ug/L (MCL) | Within the limit |
| Arsenic | Metals | Not detected ug/L (Range) | Pasadena Sources | 10 ug/L (MCL) | None detected |
| Barium | Metals | Not detected ug/L (Average) | MWD Weymouth Plant | 1000 ug/L (MCL) | Within the limit |
| Calcium | Metals | 82 mg/L (Average) | Pasadena Sources | No federal limit | Detected — no federal limit |
| Chromium, Hexavalent | Metals | 3.4 ug/L (Average) | Pasadena Water System | 0.02 ug/L (Public health goal) | At or above the limit |
| Copper | Metals | 0.26 mg/L (90th percentile) | Pasadena Water System | 1.3 mg/L (Action level) | Within the limit |
| Iron | Metals | 46 ug/L (Average) | Pasadena Sources | 300 ug/L (MCL) | Within the limit |
| Lead | Metals | Not detected ug/L (90th percentile) | Pasadena Water System | 15 ug/L (Action level) | None detected |
| Lithium | Metals | 16 ug/L (Average) | Pasadena Water System | 9 ug/L (MCL) | At or above the limit |
| Magnesium | Metals | 24 mg/L (Average) | Pasadena Sources | No federal limit | Detected — no federal limit |
| Potassium | Metals | 2.8 mg/L (Average) | MWD Weymouth Plant | No federal limit | Detected — no federal limit |
| Sodium | Metals | 47 mg/L (Average) | MWD Weymouth Plant | No federal limit | Detected — no federal limit |
| Escherichia coli (E. coli) | Microbial | 0 (Average) | Pasadena Water System Highest | 0 (MCL) | None detected |
| Total Coliform | Microbial | 1.4 % (Average) | Pasadena Water System Highest | No federal limit | Detected — no federal limit |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.005 ug/L (MCL) | None detected |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| 4:2 Fluorotelomer sulfonic acid (4:2 FTS) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| 6:2 Fluorotelomer sulfonic acid (6:2 FTS) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.005 ug/L (MCL) | None detected |
| 8:2 Fluorotelomer sulfonic acid (8:2 FTS) | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.005 ug/L (MCL) | None detected |
| 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.002 ug/L (MCL) | None detected |
| Hexafluoropropylene oxide dimer acid | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.005 ug/L (MCL) | None detected |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.005 ug/L (MCL) | None detected |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.006 ug/L (MCL) | None detected |
| Nonafluoro-3,6-dioxaheptanoic acid | PFAS ("forever chemicals") | Not detected (Average) | Pasadena Water System | 0.02 (MCL) | None detected |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.004 ug/L (MCL) | None detected |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluorobutanesulfonic acid | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluorodecanoic acid (PFDA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluorododecanoic acid (PFDoA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluoroheptanesulfonic acid (PFHpS) | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluoroheptanoic acid | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluorohexanesulfonic acid | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluorohexanoic acid | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluorononanoic acid | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.004 ug/L (MCL) | None detected |
| Perfluoropentanesulfonic acid (PFPeS) | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.004 ug/L (MCL) | None detected |
| Perfluoropentanoic acid | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.003 ug/L (MCL) | None detected |
| Perfluorotetradecanoic acid (PFTeDA) | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.008 ug/L (MCL) | None detected |
| Perfluorotridecanoic acid (PFTrDA) | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.007 ug/L (MCL) | None detected |
| Perfluoroundecanoic acid (PFUnA) | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.002 ug/L (MCL) | None detected |
| PFBA | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.005 ug/L (MCL) | None detected |
| PFOA | PFAS ("forever chemicals") | Not detected ug/L (Range) | Pasadena Water System | 0.004 ug/L (MCL) | None detected |
| PFOS | PFAS ("forever chemicals") | Not detected ug/L (Average) | Pasadena Water System | 0.004 ug/L (MCL) | None detected |
| Alkalinity | Physical & aggregate | 173 mg/L (Average) | Pasadena Sources | No federal limit | Detected — no federal limit |
| Color | Physical & aggregate | 1 (Average) | MWD Weymouth Plant | 15 (MCL) | Within the limit |
| Hardness | Physical & aggregate | 290 mg/L (Average) | Pasadena Sources | No federal limit | Detected — no federal limit |
| Odor | Physical & aggregate | 2 (Average) | MWD Weymouth Plant | 3 (MCL) | Within the limit |
| pH | Physical & aggregate | 8.6 (Average) | MWD Weymouth Plant | No federal limit | Detected — no federal limit |
| Specific Conductance | Physical & aggregate | 733 (Average) | Pasadena Sources | 1600 (MCL) | Within the limit |
| Total Dissolved Solids | Physical & aggregate | 469 mg/L (Average) | Pasadena Sources | 1000 mg/L (MCL) | Within the limit |
| Turbidity | Physical & aggregate | 0.3 NTU (Average) | Pasadena Sources | 5 NTU (MCL) | Within the limit |
| Combined Radium | Radionuclides | Not detected (Range) | MWD Weymouth Plant | 5 (MCL) | None detected |
| Gross Alpha | Radionuclides | 8 (Average) | Pasadena Sources | 15 (MCL) | Within the limit |
| Gross Beta Particle Activity | Radionuclides | Not detected (Average) | MWD Weymouth Plant | 50 (MCL) | Within the limit |
| Uranium | Radionuclides | 8.7 (Average) | Pasadena Sources | 20 (MCL) | Within the limit |
| Tetrachloroethylene | VOCs & pesticides | Not detected ug/L (Average) | MWD Weymouth Plant | 5 ug/L (MCL) | Within the limit |
| Trichloroethylene | VOCs & pesticides | Not detected ug/L (Average) | Pasadena Sources | 5 ug/L (MCL) | Within 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.
- **Perchlorate** — A chemical used in rocket fuel and fireworks that can also form during disinfection. Can interfere with thyroid hormone production; has no national enforceable limit but is regulated in some states.
- **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.
- **Aluminum** — A common element sometimes used as a treatment coagulant. Regulated only as a secondary (cosmetic) standard; high levels can discolor water.
- **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.
- **Iron** — A naturally occurring metal common in groundwater. Regulated only as a secondary (cosmetic) standard; causes rusty color, staining, and metallic taste.
- **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.
- **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.
- **11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)** — 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, a chlorinated PFAS compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **4,8-Dioxa-3H-perfluorononanoic acid (ADONA)** — ADONA, a newer-generation PFAS replacement compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **4:2 Fluorotelomer sulfonic acid (4:2 FTS)** — 4:2 fluorotelomer sulfonic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **6:2 Fluorotelomer sulfonic acid (6:2 FTS)** — 6:2 fluorotelomer sulfonic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **8:2 Fluorotelomer sulfonic acid (8:2 FTS)** — 8:2 fluorotelomer sulfonic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)** — 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, a chlorinated PFAS compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **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.
- **N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)** — N-ethyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)** — N-methyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Nonafluoro-3,6-dioxaheptanoic acid** — Nonafluoro-3,6-dioxaheptanoic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Perfluoro-3-methoxypropanoic acid (PFMPA)** — Perfluoro-3-methoxypropanoic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Perfluoro-4-methoxybutanoic acid (PFMBA)** — Perfluoro-4-methoxybutanoic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)** — Perfluoro(2-ethoxyethane)sulfonic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **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.
- **Perfluorodecanoic acid (PFDA)** — Perfluorodecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **Perfluorododecanoic acid (PFDoA)** — Perfluorododecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **Perfluoroheptanesulfonic acid (PFHpS)** — Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **Perfluoroheptanoic acid** — Perfluoroheptanoic acid, a PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **Perfluorohexanesulfonic acid** — Perfluorohexanesulfonic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **Perfluorohexanoic acid** — Perfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and widely detected.
- **Perfluorononanoic acid** — Perfluorononanoic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **Perfluoropentanesulfonic acid (PFPeS)** — Perfluoropentanesulfonic acid, a PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **Perfluoropentanoic acid** — Perfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **Perfluorotetradecanoic acid (PFTeDA)** — Perfluorotetradecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **Perfluorotridecanoic acid (PFTrDA)** — Perfluorotridecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **Perfluoroundecanoic acid (PFUnA)** — Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **PFBA** — Perfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment and the human body.
- **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.
- **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.
- **Turbidity** — A measure of cloudiness from suspended particles in the water. High turbidity can shelter microbes from disinfection; the EPA enforces it through a treatment-technique standard.
- **Combined Radium** — Combined radium-226 and radium-228 — naturally occurring radioactive elements. Long-term exposure above the federal limit increases the risk of bone cancer.
- **Gross Alpha** — Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases cancer risk.
- **Gross Beta Particle Activity** — Gross beta particle activity — a combined measure of beta-emitting radioactive substances. Long-term exposure above the federal screening level 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.
- **Tetrachloroethylene** — An industrial solvent (PCE) used in dry cleaning and degreasing. A likely human carcinogen; long-term exposure above the federal limit can damage the liver and kidneys.
- **Trichloroethylene** — An industrial solvent (TCE) used in metal degreasing. A known human carcinogen; long-term exposure above the federal limit can damage the liver.

## 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._