States → Puerto Rico
State profile · EPA SDWIS + UCMR5
Puerto Rico Drinking Water Quality
458 public water systems serve 3,328,141 people across Puerto Rico, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.
- 458
- Water systems
- 164,144
- Total violations
- 99.6%
- Systems w/ a violation
- 40.4%
- PFAS detection rate
The verdict
Across Puerto Rico, 456 of 458 water systems (99.6%) carry at least one EPA violation, and 40 of 99 UCMR5-tested systems show PFAS.
- 164,144
- Total EPA violations on record
- 21%
- Health-based (MCL / treatment)
- 99.6%
- Systems with ≥1 violation
- 40.4%
- UCMR5 PFAS detection rate
Water Systems
458
Total Violations
164,144
Violation Rate
99.6%
PFAS Detection
40.4%
40 of 99 tested
Violation Composition
How Puerto Rico's 164,144 violations break down by type, per EPA SDWIS classification.
Health-based (34,657) Monitoring/Reporting (129,487)
| Metric | Value | Share |
|---|---|---|
| Public water systems | 458 | - |
| Population served | 3,328,141 | - |
| Total violations | 164,144 | 100% |
| Health-based violations | 34,657 | 21.1% |
| Systems with violations | 456 | 99.6% |
| PFAS detection rate | 40 of 99 | 40.4% |
Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.
Largest Water Systems
Metropolitano
San Juan, PR · 1,077,332 served
Mayaguez
Mayaguez, PR · 151,555 served
Aguadilla
Aguadilla, PR · 123,885 served
Ponce Urbano
Ponce, PR · 111,926 served
Rio Blanco,vieques,culedra
Naguabo, PR · 80,759 served
El Yunque
Rio Grande, PR · 68,024 served
Arecibo Urbano
Arecibo, PR · 61,119 served
Fajardo Ceiba
Fajardo, PR · 58,011 served
Isabela
Santurce, PR · 49,419 served
Lajas
Lajas, PR · 47,531 served
Caguas Norte
Caguas, PR · 46,530 served
Santa Isabel Urbano
Santa Isabel, PR · 39,884 served
Dorado Urbano
Dorado, PR · 39,733 served
Farallon
Cayey, PR · 38,977 served
Guayama Urbano
Guayama, PR · 36,606 served
Juncos - Ceiba Sur
Juncos, PR · 36,277 served
Las Piedras Humacao
Humacao, PR · 36,032 served
Yauco
Yauco, PR · 35,618 served
Cidra Urbano
Cidra, PR · 33,957 served
Regional Villalba Toa Vaca
Santurce, PR · 33,711 served
Most Violations
#1 Ponce Urbano Ponce
2,210 #2 Juncos - Ceiba Sur Juncos
2,179 #3 Metropolitano San Juan
1,673 #4 Aguadilla Aguadilla
1,566 #5 Aibonito la Plata Aibonito
1,302 #6 Veguita Jayuya
1,241 #7 Guaraguao Ponce
1,201 #8 Alturas de Collores Jayuya
1,195 #9 Sist. Rural Graulao Utuado
1,189 #10 Mayaguez Mayaguez
1,188 #11 La Cascada Milagrosa Utuado
1,080 #12 Comunidad Juan Diego Fajardo
1,073 #13 Cubuy-Marines Canovanas
1,064 #14 Corporacion Pro Salud Y Mejora Penuelas
1,064 #15 Hacienda Rullan Utuado
1,059 Counties in Puerto Rico
San Juan Municipio
4 systems · 1,077,982 served
· 1,811 violations
Mayaguez Municipio
3 systems · 162,876 served
· 1,429 violations
Penuelas Municipio
12 systems · 133,990 served
· 7,659 violations
Rincon Municipio
1 systems · 123,885 served
· 1,566 violations
Arecibo Municipio
12 systems · 118,557 served
· 2,669 violations
Caguas Municipio
23 systems · 86,609 served
· 5,193 violations
Naguabo Municipio
5 systems · 83,376 served
· 2,551 violations
Rio Grande Municipio
5 systems · 73,495 served
· 2,133 violations
Dorado Municipio
2 systems · 71,613 served
· 828 violations
Cayey Municipio
9 systems · 62,427 served
· 1,815 violations
Fajardo Municipio
2 systems · 58,114 served
· 1,563 violations
Vega Baja Municipio
9 systems · 51,647 served
· 1,557 violations
Isabela Municipio
1 systems · 49,419 served
· 522 violations
Villalba Municipio
14 systems · 49,031 served
· 7,861 violations
Lajas Municipio
1 systems · 47,531 served
· 337 violations
Santa Isabel Municipio
5 systems · 44,670 served
· 1,017 violations
Yauco Municipio
10 systems · 41,494 served
· 3,897 violations
Juncos Municipio
3 systems · 41,043 served
· 2,524 violations
Manati Municipio
7 systems · 40,999 served
· 892 violations
Hatillo Municipio
6 systems · 39,785 served
· 1,383 violations
Patillas Municipio
12 systems · 37,543 served
· 6,428 violations
San Sebastian Municipio
5 systems · 36,986 served
· 1,552 violations
Arroyo Municipio
1 systems · 36,606 served
· 561 violations
Humacao Municipio
2 systems · 36,433 served
· 296 violations
Cidra Municipio
5 systems · 35,537 served
· 1,165 violations
San Lorenzo Municipio
17 systems · 35,423 served
· 3,795 violations
Ponce Municipio
21 systems · 35,111 served
· 7,284 violations
Lares Municipio
6 systems · 29,715 served
· 3,660 violations
Salinas Municipio
9 systems · 29,177 served
· 2,288 violations
Sabana Grande Municipio
2 systems · 29,084 served
· 675 violations
Showing top 30 of 72 counties.
Drinking Water Guides
Frequently Asked Questions
How many water systems are in Puerto Rico? ▼
Puerto Rico has 458 public water systems serving approximately 3,328,141 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Puerto Rico? ▼
Puerto Rico has 164,144 total drinking water violations on record, with 34,657 classified as health-based violations. 99.6% of water systems in the state have at least one violation.
Has PFAS been found in Puerto Rico drinking water? ▼
Of 99 water systems tested for PFAS in Puerto Rico, 40 had PFAS detected, a 40.4% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Puerto Rico water systems? ▼
Puerto Rico's violation rate is 99.6%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Puerto Rico water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources & Methodology
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on 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.