Community Water System · PWS AZ0402041
La Costa Water Users Assoc
Operator location Douglas, Arizona - smaller served population (≤ 999) at 30 people served; 113 SDWIS violations on record from groundwater sources.
- 30
- People served (this PWS)
- 113
- EPA violations (this PWS)
- 8
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
La Costa Water Users Assoc standing, high SDWIS violation third
30 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 7% is middle-third health share (≤ 23%).
The verdict
La Costa Water Users Assoc sits in the upper third of the sitemap cohort by violation count (113), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (30; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 7% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 113
- Total EPA violations on record
- 7%
- Health-based (MCL / treatment failure)
- 30
- People served by this PWS (SDWIS)
- N/A
- PFAS compounds detected (UCMR5)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Community
- Owner Type
- Public/Private
- Connections
- 16
- County
- Cochise
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 62
- Treatment Tech Violations
- 8
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Consumer Confidence Rule | Other | 34 | 2025 |
| Coliform (TCR) | MR | 16 | 2014 |
| Lead and Copper Rule | MR | 8 | 2021 |
| E. COLI | MR | 5 | 2022 |
| Revised Total Coliform Rule | TT | 4 | 2022 |
| Groundwater Rule | TT | 4 | 2023 |
| Nitrate | MR | 3 | 2000 |
| Chlorine | MR | 2 | 2008 |
| Revised Total Coliform Rule | RPT | 2 | 2020 |
| Public Notice | Other | 2 | 2021 |
| 1,2,4-Trichlorobenzene | MR | 1 | 1998 |
| cis-1,2-Dichloroethylene | MR | 1 | 1998 |
| DICHLOROMETHANE | MR | 1 | 1998 |
| o-Dichlorobenzene | MR | 1 | 1998 |
| p-Dichlorobenzene | MR | 1 | 1998 |
| trans-1,2-Dichloroethylene | MR | 1 | 1998 |
| 1,2-Dichloroethane | MR | 1 | 1998 |
| 1,2-Dichloropropane | 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 |
| Styrene | MR | 1 | 1998 |
| Arsenic | MR | 1 | 1990 |
| Fluoride | MR | 1 | 1990 |
| Chromium | MR | 1 | 1990 |
| Cadmium | MR | 1 | 1990 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 1988 |
| Barium | MR | 1 | 1990 |
Violation Count vs. the National Corpus
La Costa Water Users Assoc has 113 recorded EPA violations, 76% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 24% carry more. 7% of this system's own violations are health-based (8 of 113), and it ranks unranked by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
113 Higher than most more violations than 76% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
Population served record for La Costa Water Users Assoc
EPA SDWIS lists 30 people served and 16 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS · Arizona DEQ, Drinking Water Program
Nationwide peers
113 violations · 30 served: nearest cross-state SDWIS matches.
Cross-state systems with comparable violation load
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
What to do with La Costa Water Users Assoc
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Arizona compares on the same EPA violation measures. Arizona systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.