Community Water System · PWS CA0600008
Colusa Co. Wwd #1 - Grimes
Operator location Grimes, California - 86% of 104 violations are health-based (upper-third health share (> 23%)); groundwater source; 512 served per SDWIS.
- 512
- People served (this PWS)
- 104
- EPA violations (this PWS)
- 89
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Colusa Co. Wwd #1 - Grimes standing, high SDWIS violation third
86% of 104 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 86% is upper-third health share (> 23%). Population rank #28,311 of 29,740 among systems serving 500+.
The verdict
Colusa Co. Wwd #1 - Grimes sits in the upper third of the sitemap cohort by violation count (104), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (512; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 86% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- #28,311 of 29,740
- Population · /systems
- #1,613 of 1,701
- Population · CA
- 104
- Total EPA violations on record
- 86%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 114
- County
- Colusa
- School/Daycare
- No
- MCL Violations
- 89
- Monitoring Violations
- 15
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Arsenic | MCL | 89 | 2024 |
| Lead and Copper Rule | MR | 6 | 2023 |
| Revised Total Coliform Rule | MON | 5 | 2022 |
| Nitrate | MR | 2 | 2017 |
| Gross Alpha, Excl. Radon and U | MR | 2 | 1981 |
Violation Count vs. the National Corpus
Colusa Co. Wwd #1 - Grimes has 104 recorded EPA violations, 74% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 26% carry more. 86% of this system's own violations are health-based (89 of 104), and it ranks #28,311 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
104 Around the middle fewer violations than 26% 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 Colusa Co. Wwd #1 - Grimes
89 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for CA0600008.
Sources: EPA SDWIS · California State Water Resources Control Board, Division of Drinking Water
Nationwide peers
104 violations · 512 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.
Cross-state systems with smaller service footprints
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Colusa Co. Wwd #1 - Grimes
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.