Community Water System · PWS MO2024499
Ralls County PWSD 1
Hannibal, Missouri 63401-0000 - drinking water served from groundwater sources to 7,662 people, tracked in EPA SDWIS and UCMR5.
- 7,662
- People served
- 46
- EPA violations
- 36
- Health-based
- 3 PFAS
- UCMR5 result
The verdict
EPA records 46 drinking-water violations at Ralls County PWSD 1, 78% of them health-based - below the Missouri per-system average, and UCMR5 testing detected 3 PFAS compounds.
- 46
- Total EPA violations on record
- 78%
- Health-based (MCL / treatment failure)
- 7,662
- People served by this system
- 3
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Ralls County PWSD 1
Ralls County PWSD 1 is a local-owned community water system that delivers drinking water to 7,662 residents in Hannibal, Missouri (Ralls County) through 2,953 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 46 total violations for this system , of which 36 (78%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 8 monitoring and reporting violations are on file. The most recent violation on record dates to 2023.
The most frequently cited contaminant at this system is TTHM, recorded in 32 violations (MCL, health-based). Under EPA's UCMR5 PFAS monitoring program, 3 PFAS compounds were detected in samples collected from this system, with a maximum reported concentration of 70.1 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.
Across Missouri, EPA tracks 2,823 public water systems serving 5,855,885 people, with 201,695 cumulative violations and 54,821 health-based violations on record. About 95% of systems in the state carry at least one violation, and state-wide the average per system is 71.4 violations. Statewide, 162 of 230 UCMR5-tested systems have reported PFAS detections (70.4%).
Ralls County PWSD 1's 46 violations sit below the Missouri average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
3 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 2,953
- County
- Ralls
- School/Daycare
- No
- MCL Violations
- 36
- Monitoring Violations
- 8
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| TTHM | MCL | 32 | 2023 |
| Coliform (TCR) | MCL | 4 | 2005 |
| Revised Total Coliform Rule | MON | 4 | 2017 |
| Coliform (TCR) | MR | 4 | 2013 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 3 of 29 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFHpS | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 8/12/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 8/12/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 8/12/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 8/12/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFPeS | 8/12/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDoA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 8/12/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| NFDHA | 8/12/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| NMeFOSAA | 8/12/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| ADONA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 8/12/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFBA | 8/12/2025 | 70.10 ppt | 5.00 ppt | Detected |
| NEtFOSAA | 8/12/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBS | 8/12/2025 | 11.40 ppt | 3.00 ppt | Detected |
| PFHpA | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 8/12/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 8/12/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 8/12/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 8/12/2025 | 4.30 ppt | 4.00 ppt | Detected |
| 9Cl-PF3ONS | 8/12/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| HFPO-DA | 8/12/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 8/12/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
Verify This Water System
The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Ralls County PWSD 1.
EPA SDWIS, Federal Reports
EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:
View PWS ID MO2024499 on SDWISSource: EPA SDWIS Federal Reports Search
Missouri Drinking Water Authority
Missouri DNR, Public Drinking Water Branch is the primacy agency that licenses and inspects Ralls County PWSD 1 under EPA-delegated authority.
Open MO regulator portalViolation Timeline
Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.
| Year (latest) | Contaminant | Category | Count | EPA Record |
|---|---|---|---|---|
| 2023 | TTHM | MCL | 32 | SDWIS / MO2024499 / 2950 |
| 2017 | Revised Total Coliform Rule | MON | 4 | SDWIS / MO2024499 / 8000 |
| 2013 | Coliform (TCR) | MR | 4 | SDWIS / MO2024499 / 3100 |
| 2005 | Coliform (TCR) | MCL | 4 | SDWIS / MO2024499 / 3100 |
How Ralls County PWSD 1 Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Ralls County PWSD 1 | Missouri avg | Federal benchmark |
|---|---|---|---|
| Total violations | 46 | 71.4 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 36 | 19.4 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | 3 compounds | 70.4% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 7,662 | 2,074 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,823 regulated public water systems in Missouri.
Federal MCL reference, Safe Drinking Water Act thresholds ▼
| Contaminant | Federal MCL / Action Level | Note |
|---|---|---|
| Lead | 0 mg/L (Action Level: 0.015 mg/L) | Lead and Copper Rule treatment technique |
| Arsenic | 0.010 mg/L (10 ppb) | Health-based MCL since 2006 |
| Total Coliform | Treatment technique (RTCR) | Indicator organism, monitoring trigger |
| PFOA / PFOS (PFAS) | 4.0 ppt each (final 2024 rule) | Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026) |
| Nitrate (as N) | 10 mg/L | Acute health risk for infants |
Frequently Asked Questions
Is Ralls County PWSD 1 water safe to drink? ▼
How many people does Ralls County PWSD 1 serve? ▼
What type of violations does Ralls County PWSD 1 have? ▼
Has PFAS been detected in Ralls County PWSD 1 water? ▼
What water source does Ralls County PWSD 1 use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.