# Naperville, IL — Drinking Water Quality (2024)

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

- Page: https://www.thewatermap.com/water/il/naperville/2024
- JSON API: https://www.thewatermap.com/api/water/il/naperville/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: 14
- Contaminants with a federal limit: 11
- 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 | 1–1.2 mg/L (Range) | System-wide | 4 mg/L (MRDLG) | Within the limit |
| HAA5 | Disinfection byproducts | 11.8–34.6 ug/L (Range) | System-wide | 60 ug/L (MCL) | Within the limit |
| TTHM | Disinfection byproducts | 16.8–63.2 ug/L (Range) | System-wide | 80 ug/L (MCL) | Within the limit |
| Fluoride | Inorganic chemicals | 0.75 mg/L (Reported level) | System-wide | 4 mg/L (MCLG) | Within the limit |
| Nitrate | Inorganic chemicals | 0.36 mg/L (Reported level) | System-wide | 10 mg/L (MCLG) | Within the limit |
| Sulfate | Inorganic chemicals | 27.2 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Arsenic | Metals | 0.54 ug/L (Reported level) | System-wide | 0 ug/L (MCLG) | Detected — no federal limit |
| Barium | Metals | 0.0182–0.0191 mg/L (Range) | System-wide | 2 mg/L (MCLG) | Within the limit |
| Copper | Metals | 0.16 mg/L (90th percentile) | At the tap | 1.3 mg/L (MCLG) | Within the limit |
| Lead | Metals | 7.7 ug/L (90th percentile) | At the tap | 0 ug/L (MCLG) | Detected — no federal limit |
| Sodium | Metals | 9.1 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Turbidity | Physical & aggregate | 0.29 NTU (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Combined Radium | Radionuclides | 0.95 pCi/L (Reported level) | System-wide | 0 pCi/L (MCLG) | Detected — no federal limit |
| Gross Alpha | Radionuclides | 3.1 pCi/L (Reported level) | System-wide | 0 pCi/L (MCLG) | Detected — no federal 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.
- **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.
- **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.
- **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.
- **Sodium** — A naturally occurring salt component. Not federally regulated for health; relevant for people on sodium-restricted diets.
- **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.

## 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._