Is Las Piedras Humacao water safe to drink?

Las Piedras Humacao (PWS ID: PR0005376) has 259 recorded violations in the EPA SDWIS database. PFAS contamination has been detected in UCMR5 testing, with 1 PFAS compound found. EPA SDWIS lists this system's service population as 36,032 people using Surface Water sources.

How many people does Las Piedras Humacao serve?

EPA SDWIS reports that Las Piedras Humacao serves 36,032 people (this public water system's service population, not the municipal population of Humacao or any other city). It is a Local-owned system using Surface Water water sources with 13,495 service connections. The operator address is listed in Humacao, Puerto Rico.

What type of violations does Las Piedras Humacao have?

Las Piedras Humacao has 259 total violations: 113 health-based violations (MCL exceedances or treatment failures), 130 monitoring/reporting violations, and 108 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.

Has PFAS been detected in Las Piedras Humacao water?

Yes. UCMR5 testing detected 1 PFAS compound in Las Piedras Humacao's water supply: PFOS. PFAS are persistent "forever chemicals" that do not break down in the environment.

What water source does Las Piedras Humacao use?

Las Piedras Humacao 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.

Where does Las Piedras Humacao sit among U.S. public water systems?

According to EPA SDWIS population_served among sitemap-advertised systems (serving 500+), Las Piedras Humacao ranks #1,543 of 29,740 by people served, and #17 of 235 in Puerto Rico. Ordinals use population_served DESC among systems serving 500+ (the sitemap cohort). See /methodology#corpus-placement.

How does Las Piedras Humacao's violation count compare nationally?

Las Piedras Humacao has 259 recorded EPA SDWIS violations, fewer than 11% of the 29,740 public water systems serving 500 or more people nationwide (the same sitemap cohort used for the corpus-placement ranking above). 89% of that cohort has fewer violations than Las Piedras Humacao. A system can have zero recorded violations and still be actively monitored, and a high violation count often reflects a system that reports thoroughly, not necessarily one with worse water.

States → Puerto Rico

Community Water System · PWS PR0005376

Las Piedras Humacao

Operator location Humacao, Puerto Rico - 44% of 259 violations are health-based (upper-third health share (> 23%)); surface water source; 36,032 served per SDWIS.

Compiled by PlainWater · May 15, 2026

36,032
People served (this PWS) Larger third of systems: 259
EPA violations (this PWS) Upper third of systems: 113
Health-based (this PWS) Upper third by health-based share: 1 PFAS
UCMR5 (this PWS) Lower third of PFAS-detected systems

Follow published updates (RSS)

Las Piedras Humacao standing, high SDWIS violation third

44% of 259 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 44% is upper-third health share (> 23%). UCMR5: lower-third PFAS panel (≤ 2 compounds). Population rank #1,543 of 29,740 among systems serving 500+.

The verdict

Las Piedras Humacao sits in the upper third of the sitemap cohort by violation count (259), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (36,032; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 44% - most of this ledger is MCL or treatment-technique exceedance. UCMR5 detected 1 PFAS compound (lower-third PFAS panel (≤ 2 compounds)).

#1,543 of 29,740
Population · /systems: #17 of 235
Population · PR: 259
Total EPA violations on record: 44%
Health-based (MCL / treatment failure)

Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.

PFAS Detected

1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.

Water Safety Score

26/100

Las Piedras Humacao

Based on EPA SDWIS violation history and UCMR5 PFAS testing only, not water taste, odor, infrastructure age, or contaminants outside the federally tracked set.

Health-based violations F

113

EPA SDWIS health-based violations on record (MCL, MRDL, treatment technique)

Monitoring & reporting violations F

146

Non-health SDWIS violations (monitoring, reporting, and other compliance)

PFAS contamination B+

0.0054 µg/L

Highest PFAS compound level detected in UCMR5 testing

System Details

System Type: Community
Owner Type: Local
Connections: 13,495
County: Humacao Municipio
School/Daycare: No
MCL Violations: 5
Monitoring Violations: 130
Treatment Tech Violations: 108

Violation History

Contaminant violations recorded by EPA.

Contaminant	Category	Count	Latest
Interim Enhanced Surface Water Treatment Rule	TT	99	2010
Cryptosporidium	MR	27	2019
Turbidity	MR	23	2019
E. COLI	MR	23	2019
Lead and Copper Rule	MR	18	2015
CARBON, TOTAL	TT	9	2008
Coliform (TCR)	MR	7	2014
Coliform (TCR)	MCL	5	2015
Consumer Confidence Rule	Other	4	2020
Surface Water Treatment Rule	MR	3	2022
TTHM	MR	2	2014
Antimony, Total	MR	2	2014
Carbofuran	MR	2	2021
OXAMYL	MR	2	2021
Mercury	MR	2	1984
Nitrate	MR	2	1984
Barium	MR	2	1984
Arsenic	MR	2	1984
Fluoride	MR	2	1984
Cadmium	MR	2	1984
Selenium	MR	2	1984
Chromium	MR	2	1984
Public Notice	Other	2	2019
Total Haloacetic Acids (HAA5)	MR	2	2014
Combined Radium (-226 and -228)	MR	1	1980
Gross Alpha, Excl. Radon and U	MR	1	1980
Interim Enhanced Surface Water Treatment Rule	MR	1	2004

Violation Count vs. the National Corpus

Las Piedras Humacao has 259 recorded EPA violations, 89% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 11% carry more. 44% of this system's own violations are health-based (113 of 259), and it ranks #1,543 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)

259 Higher than most more violations than 89% 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

How many violations vs. how serious, among peer systems

Las Piedras Humacao plotted against 29 peer public water systems (500+ people served), by total violation count (x) and the share of those violations that are health-based (y). The crosshair sits at this sample's own median on each axis. A high violation count does not automatically mean a serious record: most monitoring and reporting violations are minor, not health-based.

30 public water systems (500+ people served), EPA SDWIS current release.

How to read this

Each dot is one public water system; the highlighted dot is Las Piedras Humacao. A system to the right has more recorded violations; a system higher up has a larger share of those violations classified health-based rather than monitoring or reporting.

Rare but serious: few violations, but most of them are health-based.
Frequent, mostly paperwork: many violations, but mostly monitoring or reporting, not health-based.
Clean record: below-median on both counts, the tinted corner.

View all 30 systems as a list

City of Ballinger: 372 violations, 85% health-based
Las Piedras Humacao: 259 violations, 44% health-based (this system)
Nooksack Valley Water Association: 16 violations, 31% health-based
Montgomery Co RWD 12: 7 violations, 29% health-based
Irvin Water District #6: 11 violations, 27% health-based
Ticonderoga WD: 47 violations, 26% health-based
Pine Valley Plantation: 37 violations, 24% health-based
McLouth, City Of: 29 violations, 17% health-based
Kipling Oaks 1: 25 violations, 16% health-based
South Deerfield Water Supply District: 96 violations, 16% health-based
Sunset Ridge Water District: 82 violations, 15% health-based
Orange Water Dept: 136 violations, 14% health-based
Mount Pleasant Water Sys #1: 167 violations, 11% health-based
Lake Gibson Estates: 42 violations, 2% health-based
Benson Culinary Improvement District: 212 violations, 1% health-based
Conemaugh Twp Muni Auth: 567 violations, 1% health-based
Miccosukee Service Plaza: 0 violations, 0% health-based
Brazoria - Fort Bend Counties MUD 3: 0 violations, 0% health-based
Tanglewilde Thompson Place 600: 2 violations, 0% health-based
Center Water Co: 5 violations, 0% health-based
Spring Mills Elem School/Hvs: 9 violations, 0% health-based
Great Bend Industrial Park: 14 violations, 0% health-based
Glen Park Village: 19 violations, 0% health-based
Camp Is-Sho-Da: 22 violations, 0% health-based
Hamilton: 33 violations, 0% health-based
Town of Welaka: 54 violations, 0% health-based
Township of Blairstown Dpw: 61 violations, 0% health-based
McIntosh Water & Fire Pro Authority: 71 violations, 0% health-based
Clarkdale Municipal Water System: 114 violations, 0% health-based
Eureka Water Association: 273 violations, 0% health-based

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 3 of 174 samples detected PFAS.

Contaminant	Date	Result	MRL	Status
ADONA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFTA	7/30/2024	<8.00 ppt	8.00 ppt	Not Detected
PFTrDA	7/30/2024	<7.00 ppt	7.00 ppt	Not Detected
11Cl-PF3OUdS	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
NMeFOSAA	7/30/2024	<6.00 ppt	6.00 ppt	Not Detected
PFBS	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFHpS	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFPeS	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
NFDHA	7/30/2024	<20.00 ppt	20.00 ppt	Not Detected
PFEESA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFMBA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFPeA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFMPA	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
8:2 FTS	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
4:2 FTS	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFOS	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
NEtFOSAA	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
6:2 FTS	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
PFHxS	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFNA	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
PFHpA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFOA	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
PFDA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFHxA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFUnA	7/30/2024	<2.00 ppt	2.00 ppt	Not Detected
9Cl-PF3ONS	7/30/2024	<2.00 ppt	2.00 ppt	Not Detected
PFDoA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFBA	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
HFPO-DA	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
PFTA	7/30/2024	<8.00 ppt	8.00 ppt	Not Detected
PFPeA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFDA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFOA	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
PFOS	7/30/2024	5.20 ppt	4.00 ppt	Detected
PFHxS	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFHxA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFBS	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFUnA	7/30/2024	<2.00 ppt	2.00 ppt	Not Detected
11Cl-PF3OUdS	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
6:2 FTS	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
9Cl-PF3ONS	7/30/2024	<2.00 ppt	2.00 ppt	Not Detected
4:2 FTS	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFDoA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFMPA	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
PFNA	7/30/2024	<4.00 ppt	4.00 ppt	Not Detected
PFMBA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
PFBA	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
ADONA	7/30/2024	<3.00 ppt	3.00 ppt	Not Detected
HFPO-DA	7/30/2024	<5.00 ppt	5.00 ppt	Not Detected
NMeFOSAA	7/30/2024	<6.00 ppt	6.00 ppt	Not Detected

Health-based violations on Las Piedras Humacao

113 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for PR0005376.

EPA SDWIS · PWS PR0005376

Sources: EPA SDWIS

Nationwide peers

259 violations · 36,032 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.

4 peers

Cross-state systems with similar served population

Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).

4 peers

What to do with Las Piedras Humacao

Use this system's EPA-reported record as a starting filter, not a final verdict.

See how every tracked system in Puerto Rico compares on the same EPA violation measures. Puerto Rico 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.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

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

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.