Community Water System · PWS CA4000775
Mustang Springs Mutual Water
Operator location Paso Robles, California - 40% of 15 violations are health-based (upper-third health share (> 23%)); groundwater source; 30 served per SDWIS.
- 30
- People served (this PWS)
- 15
- EPA violations (this PWS)
- 6
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Mustang Springs Mutual Water standing, low SDWIS violation third
40% of 15 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 40% is upper-third health share (> 23%).
The verdict
Mustang Springs Mutual Water is in the lower third by violation count (15; lower-third violation load (≤ 21 violations)). A low count does not mean the system is unmonitored - monitoring and reporting violations still appear in SDWIS. Population served is smaller (30; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 40% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- 15
- Total EPA violations on record
- 40%
- 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.
Based on EPA SDWIS violation history and UCMR5 PFAS testing only, not water taste, odor, infrastructure age, or contaminants outside the federally tracked set.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 16
- County
- San Luis Obispo
- School/Daycare
- No
- MCL Violations
- 6
- Monitoring Violations
- 9
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 8 | 2008 |
| Fluoride | MCL | 6 | 2022 |
| Lead and Copper Rule | MR | 1 | 1993 |
Violation Count vs. the National Corpus
Mustang Springs Mutual Water has 15 recorded EPA violations, 25% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 74% carry more. 40% of this system's own violations are health-based (6 of 15), 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)
15 Lower than most fewer violations than 74% 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
How many violations vs. how serious, among peer systems
Mustang Springs Mutual Water plotted against 29 peer public water systems (500+ people served), by total violation count (x) and the share of those violations that are health-based (y). The crosshair sits at this sample's own median on each axis. A high violation count does not automatically mean a serious record: most monitoring and reporting violations are minor, not health-based.
Violation volume vs. health-based share
Health-based violations on Mustang Springs Mutual Water
6 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for CA4000775.
Sources: EPA SDWIS · California State Water Resources Control Board, Division of Drinking Water
Nationwide peers
15 violations · 30 served: nearest cross-state SDWIS matches.
Cross-state systems with similarly light violation ledgers
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
What to do with Mustang Springs Mutual Water
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in California compares on the same EPA violation measures. California 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.