Community Water System · PWS AZ0412020
Casas Arroyo Association Inc
Sonoita, Arizona 85637 - drinking water served from groundwater sources to 27 people, tracked in EPA SDWIS and UCMR5.
- 27
- People served
- 121
- EPA violations
- 10
- Health-based
- Untested
- UCMR5 result
The verdict
EPA records 121 drinking-water violations at Casas Arroyo Association Inc, 8% of them health-based - below the Arizona per-system average.
- 121
- Total EPA violations on record
- 8%
- Health-based (MCL / treatment failure)
- 27
- People served by this system
- N/A
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Casas Arroyo Association Inc
Casas Arroyo Association Inc is a private-owned community water system that delivers drinking water to 27 residents in Sonoita, Arizona (Santa Cruz County) through 27 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 121 total violations for this system , of which 10 (8%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 76 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.
The most frequently cited contaminant at this system is Coliform (TCR), recorded in 23 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.
Across Arizona, EPA tracks 1,493 public water systems serving 7,322,166 people, with 228,944 cumulative violations and 15,663 health-based violations on record. About 98% of systems in the state carry at least one violation, and state-wide the average per system is 153.3 violations. Statewide, 145 of 152 UCMR5-tested systems have reported PFAS detections (95.4%).
Casas Arroyo Association Inc's 121 violations sit below the Arizona average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 27
- County
- Santa Cruz
- School/Daycare
- No
- MCL Violations
- 1
- Monitoring Violations
- 76
- Treatment Tech Violations
- 9
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 23 | 2014 |
| Consumer Confidence Rule | Other | 21 | 2022 |
| Chlorine | MR | 9 | 2019 |
| Nitrate | MR | 8 | 2006 |
| Public Notice | Other | 5 | 2025 |
| Groundwater Rule | TT | 5 | 2025 |
| Revised Total Coliform Rule | RPT | 4 | 2022 |
| LEAD AND COPPER RULE REVISIONS | RPT | 4 | 2024 |
| LEAD AND COPPER RULE REVISIONS | TT | 4 | 2024 |
| Lead and Copper Rule | MR | 3 | 2024 |
| Gross Alpha, Excl. Radon and U | MR | 2 | 1989 |
| E. COLI | MR | 2 | 2020 |
| Coliform (TCR) | MCL | 1 | 1999 |
| o-Dichlorobenzene | MR | 1 | 1998 |
| p-Dichlorobenzene | MR | 1 | 1998 |
| 1,1-Dichloroethylene | MR | 1 | 1998 |
| 1,2-Dichloroethane | MR | 1 | 1998 |
| Carbon tetrachloride | MR | 1 | 1998 |
| 1,1,2-Trichloroethane | MR | 1 | 1998 |
| Tetrachloroethylene | MR | 1 | 1998 |
| CHLOROBENZENE | MR | 1 | 1998 |
| Benzene | MR | 1 | 1998 |
| Toluene | MR | 1 | 1998 |
| Ethylbenzene | MR | 1 | 1998 |
| TTHM | MR | 1 | 2004 |
| Chromium | MR | 1 | 1988 |
| Selenium | MR | 1 | 1988 |
| Arsenic | MR | 1 | 1988 |
| 1,2-Dichloropropane | MR | 1 | 1998 |
| cis-1,2-Dichloroethylene | MR | 1 | 1998 |
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 Casas Arroyo Association Inc.
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 AZ0412020 on SDWISSource: EPA SDWIS Federal Reports Search
Arizona Drinking Water Authority
Arizona DEQ, Drinking Water Program is the primacy agency that licenses and inspects Casas Arroyo Association Inc under EPA-delegated authority.
Open AZ 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 |
|---|---|---|---|---|
| 2025 | Public Notice | Other | 5 | SDWIS / AZ0412020 / 7500 |
| 2025 | Groundwater Rule | TT | 5 | SDWIS / AZ0412020 / 0700 |
| 2024 | LEAD AND COPPER RULE REVISIONS | RPT | 4 | SDWIS / AZ0412020 / 5200 |
| 2024 | LEAD AND COPPER RULE REVISIONS | TT | 4 | SDWIS / AZ0412020 / 5200 |
| 2024 | Lead and Copper Rule | MR | 3 | SDWIS / AZ0412020 / 5000 |
| 2022 | Consumer Confidence Rule | Other | 21 | SDWIS / AZ0412020 / 7000 |
| 2022 | Revised Total Coliform Rule | RPT | 4 | SDWIS / AZ0412020 / 8000 |
| 2020 | E. COLI | MR | 2 | SDWIS / AZ0412020 / 3014 |
| 2019 | Chlorine | MR | 9 | SDWIS / AZ0412020 / 0999 |
| 2014 | Coliform (TCR) | MR | 23 | SDWIS / AZ0412020 / 3100 |
| 2006 | Nitrate | MR | 8 | SDWIS / AZ0412020 / 1040 |
| 2004 | TTHM | MR | 1 | SDWIS / AZ0412020 / 2950 |
| 2004 | Total Haloacetic Acids (HAA5) | MR | 1 | SDWIS / AZ0412020 / 2456 |
| 1999 | Coliform (TCR) | MCL | 1 | SDWIS / AZ0412020 / 3100 |
| 1998 | o-Dichlorobenzene | MR | 1 | SDWIS / AZ0412020 / 2968 |
How Casas Arroyo Association Inc Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Casas Arroyo Association Inc | Arizona avg | Federal benchmark |
|---|---|---|---|
| Total violations | 121 | 153.3 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 10 | 10.5 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | None | 95.4% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 27 | 4,904 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 1,493 regulated public water systems in Arizona.
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 Casas Arroyo Association Inc water safe to drink? ▼
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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.