Community Water System · PWS CO0162418
Johnstown Town Of
Operator location Johnstown, Colorado - larger served population (> 3,309) at 24,725 people served; 294 SDWIS violations on record from surface water sources.
- 24,725
- People served (this PWS)
- 294
- EPA violations (this PWS)
- 21
- Health-based (this PWS)
- No PFAS
- UCMR5 (this PWS)
Johnstown Town Of standing, high SDWIS violation third
24,725 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 7% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #2,259 of 29,740 among systems serving 500+.
The verdict
Johnstown Town Of sits in the upper third of the sitemap cohort by violation count (294), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (24,725; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 7% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #2,259 of 29,740
- Population · /systems
- #50 of 551
- Population · CO
- 294
- Total EPA violations on record
- 7%
- 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
- 6,990
- County
- Weld
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 254
- Treatment Tech Violations
- 21
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Interim Enhanced Surface Water Treatment Rule | MR | 43 | 2021 |
| Surface Water Treatment Rule | MR | 18 | 2022 |
| CARBON, TOTAL | TT | 13 | 2020 |
| CARBON, TOTAL | MR | 11 | 2017 |
| TTHM | MR | 11 | 2021 |
| Total Haloacetic Acids (HAA5) | MR | 11 | 2021 |
| Fluoride | MR | 10 | 2017 |
| Lead and Copper Rule | MR | 10 | 2019 |
| Nitrate | MR | 8 | 2017 |
| Surface Water Treatment Rule | TT | 8 | 2021 |
| Barium | MR | 6 | 2017 |
| Cadmium | MR | 6 | 2017 |
| Nickel | MR | 6 | 2017 |
| Thallium, Total | MR | 6 | 2017 |
| Selenium | MR | 6 | 2017 |
| Beryllium, Total | MR | 6 | 2017 |
| Mercury | MR | 6 | 2017 |
| Antimony, Total | MR | 6 | 2017 |
| Chromium | MR | 6 | 2017 |
| Arsenic | MR | 6 | 2017 |
| Revised Total Coliform Rule | Other | 4 | 2018 |
| cis-1,2-Dichloroethylene | MR | 3 | 2008 |
| Xylenes, Total | MR | 3 | 2008 |
| DICHLOROMETHANE | MR | 3 | 2008 |
| p-Dichlorobenzene | MR | 3 | 2008 |
| Vinyl chloride | MR | 3 | 2008 |
| 1,1-Dichloroethylene | MR | 3 | 2008 |
| trans-1,2-Dichloroethylene | MR | 3 | 2008 |
| 1,2-Dichloroethane | MR | 3 | 2008 |
| 1,1,1-Trichloroethane | MR | 3 | 2008 |
Violation Count vs. the National Corpus
Johnstown Town Of has 294 recorded EPA violations, 91% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 9% carry more. 7% of this system's own violations are health-based (21 of 294), and it ranks #2,259 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)
294 Higher than most more violations than 91% 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
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 116 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFOA | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| ADONA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 8/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 8/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFOS | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFBS | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 8/7/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFDA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFPeS | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFEESA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 8/22/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFEESA | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 8/22/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 4:2 FTS | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 8/22/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 8/22/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFDA | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 8/22/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 8/22/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFOA | 8/22/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 8/22/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFDoA | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| ADONA | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 8/22/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 8:2 FTS | 8/22/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHxA | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 8/22/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| NEtFOSAA | 8/22/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFNA | 8/22/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTA | 8/22/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFPeS | 8/22/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 8/22/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 8/22/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
Population served record for Johnstown Town Of
EPA SDWIS lists 24,725 people served and 6,990 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS · Colorado Department of Public Health and Environment, Water Quality Control
Nationwide peers
294 violations · 24,725 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 similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Johnstown Town Of
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Colorado compares on the same EPA violation measures. Colorado 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.