Community Water System · PWS PR0003772
Lago Guajataca
Isabela, Puerto Rico 00662 - drinking water served from surface water sources to 11,187 people, tracked in EPA SDWIS and UCMR5.
- 11,187
- People served
- 573
- EPA violations
- 314
- Health-based
- No PFAS
- UCMR5 result
The verdict
EPA records 573 drinking-water violations at Lago Guajataca, 55% of them health-based - above the Puerto Rico per-system average.
- 573
- Total EPA violations on record
- 55%
- Health-based (MCL / treatment failure)
- 11,187
- People served by this system
- 0
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Lago Guajataca
Lago Guajataca is a local-owned community water system that delivers drinking water to 11,187 residents in Isabela, Puerto Rico (San Sebastian Municipio County) through 4,190 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 573 total violations for this system , of which 314 (55%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 246 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.
The most frequently cited contaminant at this system is Surface Water Treatment Rule, recorded in 224 violations (TT, health-based). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.
Across Puerto Rico, EPA tracks 458 public water systems serving 3,328,141 people, with 164,144 cumulative violations and 34,657 health-based violations on record. About 100% of systems in the state carry at least one violation, and state-wide the average per system is 358.4 violations. Statewide, 40 of 99 UCMR5-tested systems have reported PFAS detections (40.4%).
Lago Guajataca's 573 violations sit above the Puerto Rico 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
- 4,190
- County
- San Sebastian Municipio
- School/Daycare
- No
- MCL Violations
- 51
- Monitoring Violations
- 246
- Treatment Tech Violations
- 263
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Surface Water Treatment Rule | TT | 224 | 2003 |
| Surface Water Treatment Rule | MR | 69 | 2024 |
| Lead and Copper Rule | MR | 38 | 2016 |
| Interim Enhanced Surface Water Treatment Rule | TT | 37 | 2022 |
| Cryptosporidium | MR | 35 | 2019 |
| Turbidity | MR | 33 | 2019 |
| E. COLI | MR | 33 | 2019 |
| TTHM | MCL | 25 | 2020 |
| Total Haloacetic Acids (HAA5) | MCL | 21 | 2020 |
| TTHM | MR | 7 | 2016 |
| Coliform (TCR) | MR | 5 | 1998 |
| Coliform (TCR) | MCL | 5 | 2004 |
| Total Haloacetic Acids (HAA5) | MR | 5 | 2016 |
| Consumer Confidence Rule | Other | 3 | 2020 |
| CARBON, TOTAL | TT | 2 | 2017 |
| 1,1,1-Trichloroethane | MR | 1 | 1996 |
| Tetrachloroethylene | MR | 1 | 1996 |
| Toluene | MR | 1 | 1996 |
| 1,2,4-Trichlorobenzene | MR | 1 | 1996 |
| o-Dichlorobenzene | MR | 1 | 1996 |
| trans-1,2-Dichloroethylene | MR | 1 | 1996 |
| 1,2-Dichloroethane | MR | 1 | 1996 |
| p-Dichlorobenzene | MR | 1 | 1996 |
| Ethylbenzene | MR | 1 | 1996 |
| 1,1-Dichloroethylene | MR | 1 | 1996 |
| Benzene | MR | 1 | 1996 |
| cis-1,2-Dichloroethylene | MR | 1 | 1996 |
| 1,2-Dichloropropane | MR | 1 | 1996 |
| Xylenes, Total | MR | 1 | 1996 |
| DICHLOROMETHANE | MR | 1 | 1996 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 116 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFPeA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| ADONA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 8/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 8/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 8/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 8/22/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFUnA | 8/22/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFMBA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 8/22/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 8/22/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 8/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 8/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 8/22/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 8/22/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 8/22/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 8/22/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 8/22/2024 | <6.00 ppt | 6.00 ppt | Not Detected |
| NEtFOSAA | 8/22/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 8/22/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFTA | 8/22/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| 9Cl-PF3ONS | 8/22/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFEESA | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 5/21/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMBA | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 5/21/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeA | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 5/21/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFPeS | 5/21/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTrDA | 5/21/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 5/21/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBS | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOS | 5/21/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFBA | 5/21/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFDA | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 5/21/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxA | 5/21/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 5/21/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 5/21/2025 | <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 Lago Guajataca.
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 PR0003772 on SDWISSource: EPA SDWIS Federal Reports Search
Puerto Rico Drinking Water Authority
Puerto Rico's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.
Find PR regulator via EPA SDWISViolation 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 |
|---|---|---|---|---|
| 2024 | Surface Water Treatment Rule | MR | 69 | SDWIS / PR0003772 / 0200 |
| 2022 | Interim Enhanced Surface Water Treatment Rule | TT | 37 | SDWIS / PR0003772 / 0300 |
| 2020 | TTHM | MCL | 25 | SDWIS / PR0003772 / 2950 |
| 2020 | Total Haloacetic Acids (HAA5) | MCL | 21 | SDWIS / PR0003772 / 2456 |
| 2020 | Consumer Confidence Rule | Other | 3 | SDWIS / PR0003772 / 7000 |
| 2019 | Cryptosporidium | MR | 35 | SDWIS / PR0003772 / 3015 |
| 2019 | Turbidity | MR | 33 | SDWIS / PR0003772 / 0100 |
| 2019 | E. COLI | MR | 33 | SDWIS / PR0003772 / 3014 |
| 2017 | CARBON, TOTAL | TT | 2 | SDWIS / PR0003772 / 2920 |
| 2016 | Lead and Copper Rule | MR | 38 | SDWIS / PR0003772 / 5000 |
| 2016 | TTHM | MR | 7 | SDWIS / PR0003772 / 2950 |
| 2016 | Total Haloacetic Acids (HAA5) | MR | 5 | SDWIS / PR0003772 / 2456 |
| 2004 | Coliform (TCR) | MCL | 5 | SDWIS / PR0003772 / 3100 |
| 2003 | Surface Water Treatment Rule | TT | 224 | SDWIS / PR0003772 / 0200 |
| 1998 | Coliform (TCR) | MR | 5 | SDWIS / PR0003772 / 3100 |
How Lago Guajataca Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Lago Guajataca | Puerto Rico avg | Federal benchmark |
|---|---|---|---|
| Total violations | 573 | 358.4 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 314 | 75.7 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | None | 40.4% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 11,187 | 7,267 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 458 regulated public water systems in Puerto Rico.
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 Lago Guajataca water safe to drink? ▼
How many people does Lago Guajataca serve? ▼
What type of violations does Lago Guajataca have? ▼
Has PFAS been detected in Lago Guajataca water? ▼
What water source does Lago Guajataca 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.