Water Quality in Caldwell, ID: 24 Violations — Grade C
Grade C · Score 64/100 · 5 water systems · Updated 2026-05-03
Caldwell's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
Water systems in Caldwell, ID have accumulated 24 EPA violations across the full compliance record — a dataset that captures reportable health-based exceedances, monitoring lapses, and enforcement actions filed with the federal Safe Drinking Water Information System.
Water Quality by ZIP Code in Caldwell
Water quality varies across Caldwell's 3 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 83606 | C | 62 | 8 | 0 | View report → |
| 83605 | C | 65 | 8 | 0 | View report → |
| 83607 | C | 65 | 8 | 0 | View report → |
Water Quality Overview
Caldwell, Idaho receives a water quality grade of C with an overall score of 64 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Caldwell have accumulated 24 EPA violations (all monitoring/reporting type). These violations are tracked across 3 ZIP codes serving approximately 75,858 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Caldwell's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across Caldwell water systems is 0.0080 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Radon Risk
Caldwell is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Caldwell
Caldwell is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 75,858 people across 3 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 30 enforcement actions against water systems serving Caldwell. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Caldwell
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Caldwell Water Systems
The following contaminants have been detected or caused violations across Caldwell's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Stage 1 DBP Rule | Treatment Technique | N/A | 15 | 3 | No |
| Barium | Inorganic | 2 mg/L | 6 | 3 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 3 | 3 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Caldwell. Recent actions:
| Date | Action Type |
|---|---|
| 2025-08-12 | State Order Extension |
| 2024-10-14 | State Informal Enforcement |
| 2024-10-11 | State Informal Action |
| 2024-06-16 | State Order Extension |
| 2024-02-15 | State Informal Enforcement |
| 2024-02-12 | State Informal Action |
| 2023-12-27 | State Order Extension |
| 2023-08-10 | State Informal Enforcement |
| 2023-08-07 | State Informal Action |
| 2023-06-09 | State Informal Enforcement |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-08-12.
Caldwell vs. Nearby Idaho Cities
How Caldwell's water quality compares to similar cities in Idaho:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Caldwell | C | 24 | 5 | 75,858 |
| Pocatello | C | 6 | 5 | 58,929 |
| Fort Hall | D | 0 | 1 | 58,231 |
| Idaho Falls | B | 77 | 5 | 94,659 |
Water Quality by ZIP Code in Caldwell
Water quality varies across Caldwell's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
Common Questions About Caldwell Water
These are the most common questions residents search for about water quality in Caldwell, Idaho:
Is Caldwell water hard or soft? Water hardness varies by source. Caldwell's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Caldwell tap water? Caldwell's water receives a grade of C (64/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Caldwell? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Caldwell vs. Idaho Average
Understanding how Caldwell compares to the broader Idaho average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Caldwell.
ZIP Codes in Caldwell
Caldwell spans 3 ZIP codes. The ZIP with the lowest water quality score is 83605. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.