# Slo Cwwd No. 23 - Santa Margarita — San Luis Obispo, Ca, CA — Drinking Water Quality (2023)

> Contaminant levels for the Slo Cwwd No. 23 - Santa Margarita — San Luis Obispo, Ca, CA public water system from its 2023 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/slo-cwwd-no-23-santa-margarita-san-luis-obispo-ca/2023
- JSON API: https://www.thewatermap.com/api/water/ca/slo-cwwd-no-23-santa-margarita-san-luis-obispo-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: 17
- Contaminants with a federal limit: 3
- 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 |
|---|---|---|---|---|---|
| Chlorine | Disinfectants | 1.66 mg/L (Average) | System-wide | No federal limit | Within the limit |
| HAA5 | Disinfection byproducts | Not detected ug/L (Average) | System-wide | No federal limit | None detected |
| TTHM | Disinfection byproducts | 4 ug/L (Average) | System-wide | No federal limit | Within the limit |
| Chloride | Inorganic chemicals | 17 mg/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Fluoride | Inorganic chemicals | Not detected mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| Nitrate | Inorganic chemicals | 0.82 mg/L (Average) | System-wide | 10 mg/L (MCL) | Within the limit |
| Arsenic | Metals | 3.8 ug/L (Average) | System-wide | No federal limit | Within the limit |
| Chromium, Hexavalent | Metals | 0.75 ug/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Copper | Metals | 930 ug/L (90th percentile) | At the tap | No federal limit | Within the limit |
| Iron | Metals | 171 ug/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Lead | Metals | 1 ug/L (90th percentile) | At the tap | No federal limit | Within the limit |
| Color | Physical & aggregate | Not detected (Average) | System-wide | No federal limit | Detected — no federal limit |
| Odor | Physical & aggregate | Not detected (Average) | System-wide | No federal limit | Detected — no federal limit |
| pH | Physical & aggregate | 7.77 (Average) | System-wide | No federal limit | Detected — no federal limit |
| Specific Conductance | Physical & aggregate | 610 (Average) | System-wide | No federal limit | Detected — no federal limit |
| Turbidity | Physical & aggregate | 0.03 NTU (Average) | System-wide | No federal limit | Within the limit |
| Gross Alpha | Radionuclides | 2.62 pCi/L (Average) | System-wide | 15 pCi/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.
- **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.
- **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.
- **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.
- **Color** — A measure of visible tint in the water. Regulated only as a secondary (cosmetic) standard.
- **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.
- **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.
- **Gross Alpha** — Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases 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._