Community Water System · PWS CO0107471
Left Hand WD
Niwot, Colorado 80544 - drinking water served from surface water sources to 20,280 people, tracked in EPA SDWIS and UCMR5.
- 20,280
- People served
- 213
- EPA violations
- 4
- Health-based
- No PFAS
- UCMR5 result
The verdict
EPA records 213 drinking-water violations at Left Hand WD, 2% of them health-based - above the Colorado per-system average.
- 213
- Total EPA violations on record
- 2%
- Health-based (MCL / treatment failure)
- 20,280
- People served by this system
- 0
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Left Hand WD
Left Hand WD is a local-owned community water system that delivers drinking water to 20,280 residents in Niwot, Colorado (Boulder County) through 7,769 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 213 total violations for this system , of which 4 (2%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 205 monitoring and reporting violations are on file. The most recent violation on record dates to 2017.
The most frequently cited contaminant at this system is OXAMYL, recorded in 6 violations (MR). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.
Across Colorado, EPA tracks 2,193 public water systems serving 7,473,456 people, with 238,796 cumulative violations and 30,589 health-based violations on record. About 93% of systems in the state carry at least one violation, and state-wide the average per system is 108.9 violations. Statewide, 98 of 163 UCMR5-tested systems have reported PFAS detections (60.1%).
Left Hand WD's 213 violations sit above the Colorado average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 7,769
- County
- Boulder
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 205
- Treatment Tech Violations
- 4
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| OXAMYL | MR | 6 | 2005 |
| Simazine | MR | 6 | 2005 |
| Hexachlorocyclopentadiene | MR | 6 | 2005 |
| Carbofuran | MR | 6 | 2005 |
| Heptachlor | MR | 6 | 2005 |
| Heptachlor epoxide | MR | 6 | 2005 |
| 2,4-D | MR | 6 | 2005 |
| 2,4,5-TP | MR | 6 | 2005 |
| Pentachlorophenol | MR | 6 | 2005 |
| Endrin | MR | 6 | 2005 |
| Di(2-ethylhexyl) adipate | MR | 6 | 2005 |
| Di(2-ethylhexyl) phthalate | MR | 6 | 2005 |
| Picloram | MR | 6 | 2005 |
| Atrazine | MR | 6 | 2005 |
| LASSO | MR | 6 | 2005 |
| HEXACHLOROBENZENE | MR | 6 | 2005 |
| Benzo(a)pyrene | MR | 6 | 2005 |
| Total Polychlorinated Biphenyls (PCB) | MR | 6 | 2005 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 6 | 2005 |
| ETHYLENE DIBROMIDE | MR | 6 | 2005 |
| Chlordane | MR | 6 | 2005 |
| Methoxychlor | MR | 6 | 2005 |
| BHC-GAMMA | MR | 6 | 2005 |
| Aldicarb sulfoxide | MR | 6 | 2005 |
| Endothall | MR | 6 | 2005 |
| Aldicarb | MR | 6 | 2005 |
| Aldicarb sulfone | MR | 6 | 2005 |
| Dinoseb | MR | 6 | 2005 |
| Diquat | MR | 6 | 2005 |
| Dalapon | MR | 6 | 2005 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 232 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFMBA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 9/7/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| NEtFOSAA | 9/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 9/7/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFHpS | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 9/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTA | 9/7/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFEESA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 9/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 9/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 9/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 9/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFOS | 9/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFBS | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 9/7/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| HFPO-DA | 9/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFNA | 9/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 9/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 9/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 9/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 9/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 9/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 9/16/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFDoA | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 9/16/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| NMeFOSAA | 9/16/2024 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTrDA | 9/16/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFTA | 9/16/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFOS | 9/16/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpA | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 9/16/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFBS | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 4:2 FTS | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 9/16/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFNA | 9/16/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMBA | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 9/16/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 9/16/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
Verify This Water System
The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Left Hand WD.
EPA SDWIS, Federal Reports
EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:
View PWS ID CO0107471 on SDWISSource: EPA SDWIS Federal Reports Search
Colorado Drinking Water Authority
Colorado Department of Public Health and Environment, Water Quality Control is the primacy agency that licenses and inspects Left Hand WD under EPA-delegated authority.
Open CO regulator portalSource: Colorado Department of Public Health and Environment, Water Quality Control
Violation Timeline
Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.
| Year (latest) | Contaminant | Category | Count | EPA Record |
|---|---|---|---|---|
| 2017 | E. COLI | MR | 4 | SDWIS / CO0107471 / 3014 |
| 2017 | Turbidity | MR | 4 | SDWIS / CO0107471 / 0100 |
| 2017 | Cryptosporidium | MR | 4 | SDWIS / CO0107471 / 3015 |
| 2015 | Total Haloacetic Acids (HAA5) | MR | 3 | SDWIS / CO0107471 / 2456 |
| 2013 | Nitrate | MR | 3 | SDWIS / CO0107471 / 1040 |
| 2005 | OXAMYL | MR | 6 | SDWIS / CO0107471 / 2036 |
| 2005 | Simazine | MR | 6 | SDWIS / CO0107471 / 2037 |
| 2005 | Hexachlorocyclopentadiene | MR | 6 | SDWIS / CO0107471 / 2042 |
| 2005 | Carbofuran | MR | 6 | SDWIS / CO0107471 / 2046 |
| 2005 | Heptachlor | MR | 6 | SDWIS / CO0107471 / 2065 |
| 2005 | Heptachlor epoxide | MR | 6 | SDWIS / CO0107471 / 2067 |
| 2005 | 2,4-D | MR | 6 | SDWIS / CO0107471 / 2105 |
| 2005 | 2,4,5-TP | MR | 6 | SDWIS / CO0107471 / 2110 |
| 2005 | Pentachlorophenol | MR | 6 | SDWIS / CO0107471 / 2326 |
| 2005 | Endrin | MR | 6 | SDWIS / CO0107471 / 2005 |
How Left Hand WD Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Left Hand WD | Colorado avg | Federal benchmark |
|---|---|---|---|
| Total violations | 213 | 108.9 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 4 | 13.9 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | None | 60.1% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 20,280 | 3,408 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,193 regulated public water systems in Colorado.
Federal MCL reference, Safe Drinking Water Act thresholds ▼
| Contaminant | Federal MCL / Action Level | Note |
|---|---|---|
| Lead | 0 mg/L (Action Level: 0.015 mg/L) | Lead and Copper Rule treatment technique |
| Arsenic | 0.010 mg/L (10 ppb) | Health-based MCL since 2006 |
| Total Coliform | Treatment technique (RTCR) | Indicator organism, monitoring trigger |
| PFOA / PFOS (PFAS) | 4.0 ppt each (final 2024 rule) | Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026) |
| Nitrate (as N) | 10 mg/L | Acute health risk for infants |
Frequently Asked Questions
Is Left Hand WD water safe to drink? ▼
How many people does Left Hand WD serve? ▼
What type of violations does Left Hand WD have? ▼
Has PFAS been detected in Left Hand WD water? ▼
What water source does Left Hand WD use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.