Community Water System · PWS PR0002842

Rio Arriba

Arecibo, Puerto Rico 00612 - drinking water served from surface water sources to 753 people, tracked in EPA SDWIS and UCMR5.

Compiled by PlainWater Editorial, Drinking Water Quality Editorial Team · May 15, 2026

753
People served: 287
EPA violations: 98
Health-based: Untested
UCMR5 result

The verdict

EPA records 287 drinking-water violations at Rio Arriba, 34% of them health-based - below the Puerto Rico per-system average.

287
Total EPA violations on record: 34%
Health-based (MCL / treatment failure): 753
People served by this system: N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Rio Arriba

Rio Arriba is a local-owned community water system that delivers drinking water to 753 residents in Arecibo, Puerto Rico (Arecibo Municipio County) through 282 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 287 total violations for this system , of which 98 (34%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 177 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 92 violations (TT, health-based). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

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%).

Rio Arriba's 287 violations sit below 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.

Population Served

753

Total Violations

287

Health-Based Violations

Water Source

Surface Water

System Details

System Type: Community
Owner Type: Local
Connections: 282
County: Arecibo Municipio
School/Daycare: No
MCL Violations: 3
Monitoring Violations: 177
Treatment Tech Violations: 95

Violation History

Contaminant violations recorded by EPA.

Contaminant	Category	Count	Latest
Surface Water Treatment Rule	TT	92	2005
Surface Water Treatment Rule	MR	51	2023
Lead and Copper Rule	MR	13	2015
Consumer Confidence Rule	Other	5	2022
E. COLI	MR	4	2018
Nitrate	MR	4	2024
Coliform (TCR)	MCL	3	2007
Interim Enhanced Surface Water Treatment Rule	TT	3	2006
1,2,4-Trichlorobenzene	MR	3	2009
cis-1,2-Dichloroethylene	MR	3	2009
Xylenes, Total	MR	3	2009
o-Dichlorobenzene	MR	3	2009
1,1-Dichloroethylene	MR	3	2009
1,2-Dichloroethane	MR	3	2009
Tetrachloroethylene	MR	3	2009
CHLOROBENZENE	MR	3	2009
Ethylbenzene	MR	3	2009
Styrene	MR	3	2009
TTHM	MR	3	2018
p-Dichlorobenzene	MR	3	2009
Vinyl chloride	MR	3	2009
trans-1,2-Dichloroethylene	MR	3	2009
Trichloroethylene	MR	3	2009
Toluene	MR	3	2009
1,2-Dichloropropane	MR	3	2009
Benzene	MR	3	2009
1,1,1-Trichloroethane	MR	3	2009
Carbon tetrachloride	MR	3	2009
DICHLOROMETHANE	MR	3	2009
1,1,2-Trichloroethane	MR	3	2009

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 Rio Arriba.

Federal Source of Truth

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 PR0002842 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

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 SDWIS

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
2024	Nitrate	MR	4	SDWIS / PR0002842 / 1040
2023	Surface Water Treatment Rule	MR	51	SDWIS / PR0002842 / 0200
2022	Consumer Confidence Rule	Other	5	SDWIS / PR0002842 / 7000
2019	Revised Total Coliform Rule	MON	3	SDWIS / PR0002842 / 8000
2018	E. COLI	MR	4	SDWIS / PR0002842 / 3014
2018	TTHM	MR	3	SDWIS / PR0002842 / 2950
2018	Total Haloacetic Acids (HAA5)	MR	2	SDWIS / PR0002842 / 2456
2015	Lead and Copper Rule	MR	13	SDWIS / PR0002842 / 5000
2010	Endrin	MR	2	SDWIS / PR0002842 / 2005
2010	Heptachlor	MR	2	SDWIS / PR0002842 / 2065
2010	Heptachlor epoxide	MR	2	SDWIS / PR0002842 / 2067
2010	Total Polychlorinated Biphenyls (PCB)	MR	2	SDWIS / PR0002842 / 2383
2010	Chlordane	MR	2	SDWIS / PR0002842 / 2959
2010	HEXACHLOROBENZENE	MR	2	SDWIS / PR0002842 / 2274
2010	Methoxychlor	MR	2	SDWIS / PR0002842 / 2015

How Rio Arriba Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric	Rio Arriba	Puerto Rico avg	Federal benchmark
Total violations	287	358.4	SDWA compliance, any non-zero count is a recorded breach
Health-based violations	98	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	753	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 Rio Arriba water safe to drink? ▼

Rio Arriba (PWS ID: PR0002842) has 287 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 753 people using Surface Water sources.

How many people does Rio Arriba serve? ▼

Rio Arriba serves 753 people in Arecibo, Puerto Rico. It is a Local-owned system using Surface Water water sources with 282 service connections.

What type of violations does Rio Arriba have? ▼

Rio Arriba has 287 total violations: 98 health-based violations (MCL exceedances or treatment failures), 177 monitoring/reporting violations, and 95 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.

Has PFAS been detected in Rio Arriba water? ▼

No PFAS testing data is available for Rio Arriba under the EPA's UCMR5 monitoring program.

What water source does Rio Arriba use? ▼

Rio Arriba uses Surface Water as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.

Where does this data come from? ▼

All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.

Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. This data is provided for informational purposes only.

Read our methodology - how this data is sourced, computed, and verified.

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 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.