Non-Transient Non-Community Water System · PWS CA2100582
Nicasio School
Operator location Nicasio, California - 96% of 56 violations are health-based (upper-third health share (> 23%)); surface water source; 48 served per SDWIS.
- 48
- People served (this PWS)
- 56
- EPA violations (this PWS)
- 54
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Nicasio School standing, mid SDWIS violation third
96% of 56 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 96% is upper-third health share (> 23%).
The verdict
Nicasio School lands in the middle third by violation volume (56), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is smaller (48; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 96% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- 56
- Total EPA violations on record
- 96%
- Health-based (MCL / treatment failure)
- 48
- 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
- Non-Transient Non-Community
- Owner Type
- Private
- Connections
- 5
- County
- Marin
- School/Daycare
- Yes
- MCL Violations
- 54
- Monitoring Violations
- 2
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Total Haloacetic Acids (HAA5) | MCL | 50 | 2021 |
| Coliform (TCR) | MCL | 4 | 2006 |
| Lead and Copper Rule | MR | 2 | 2006 |
Violation Count vs. the National Corpus
Nicasio School has 56 recorded EPA violations, 60% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 40% carry more. 96% of this system's own violations are health-based (54 of 56), 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)
56 Around the middle fewer violations than 40% 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
Health-based violations on Nicasio School
54 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for CA2100582.
Sources: EPA SDWIS · California State Water Resources Control Board, Division of Drinking Water
Nationwide peers
56 violations · 48 served: nearest cross-state SDWIS matches.
Cross-state systems near this violation count
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
What to do with Nicasio School
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.