Is Chehalis Water Department water safe to drink?

Chehalis Water Department (PWS ID: WA5312250) has 42 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. EPA SDWIS lists this system's service population as 11,426 people using Surface Water sources.

How many people does Chehalis Water Department serve?

EPA SDWIS reports that Chehalis Water Department serves 11,426 people (this public water system's service population, not the municipal population of Chehalis or any other city). It is a Local-owned system using Surface Water water sources with 3,853 service connections. The operator address is listed in Chehalis, Washington.

What type of violations does Chehalis Water Department have?

Chehalis Water Department has 42 total violations: 6 health-based violations (MCL exceedances or treatment failures), 33 monitoring/reporting violations, and 3 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.

Has PFAS been detected in Chehalis Water Department water?

No. Chehalis Water Department was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.

What water source does Chehalis Water Department use?

Chehalis Water Department 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 Chehalis Water Department sit among U.S. public water systems?

According to EPA SDWIS population_served among sitemap-advertised systems (serving 500+), Chehalis Water Department ranks #4,260 of 29,740 by people served, and #126 of 766 in Washington. Ordinals use population_served DESC among systems serving 500+ (the sitemap cohort). See /methodology#corpus-placement.

How does Chehalis Water Department's violation count compare nationally?

Chehalis Water Department has 42 recorded EPA SDWIS violations, fewer than 48% of the 29,740 public water systems serving 500 or more people nationwide (the same sitemap cohort used for the corpus-placement ranking above). 52% of that cohort has fewer violations than Chehalis Water Department. 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 → Washington

Community Water System · PWS WA5312250

Chehalis Water Department

Operator location Chehalis, Washington - larger served population (> 3,309) at 11,426 people served; 42 SDWIS violations on record from surface water sources.

Compiled by PlainWater · May 15, 2026

11,426
People served (this PWS) Larger third of systems: 42
EPA violations (this PWS) Middle third of systems: 6
Health-based (this PWS) Middle third by health-based share: No PFAS
UCMR5 (this PWS) Tested, none detected

Follow published updates (RSS)

Chehalis Water Department standing, mid SDWIS violation third

11,426 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 14% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #4,260 of 29,740 among systems serving 500+.

The verdict

Chehalis Water Department lands in the middle third by violation volume (42), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is large (11,426; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 14% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.

#4,260 of 29,740
Population · /systems: #126 of 766
Population · WA: 42
Total EPA violations on record: 14%
Health-based (MCL / treatment failure)

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

Water Safety Score

35/100

Chehalis Water Department

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

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

Monitoring & reporting violations F

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

PFAS contamination N/A

Tested, none detected

Highest PFAS compound level detected in UCMR5 testing

System Details

System Type: Community
Owner Type: Local
Connections: 3,853
County: Lewis
School/Daycare: No
MCL Violations: 3
Monitoring Violations: 33
Treatment Tech Violations: 3

Violation History

Contaminant violations recorded by EPA.

Contaminant	Category	Count	Latest
Surface Water Treatment Rule	TT	3	2005
Coliform (TCR)	MCL	3	1992
Endrin	MR	2	2006
Methoxychlor	MR	2	2006
Toxaphene	MR	2	2006
Hexachlorocyclopentadiene	MR	2	2006
Atrazine	MR	2	2006
Heptachlor	MR	2	2006
Pentachlorophenol	MR	2	2006
Chlordane	MR	2	2006
BHC-GAMMA	MR	2	2006
Di(2-ethylhexyl) adipate	MR	2	2006
Simazine	MR	2	2006
Di(2-ethylhexyl) phthalate	MR	2	2006
LASSO	MR	2	2006
Benzo(a)pyrene	MR	2	2006
HEXACHLOROBENZENE	MR	2	2006
Consumer Confidence Rule	Other	2	2024
Heptachlor epoxide	MR	2	2006
Gross Alpha, Excl. Radon and U	MR	1	1979

Violation Count vs. the National Corpus

Chehalis Water Department has 42 recorded EPA violations, 52% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 48% carry more. 14% of this system's own violations are health-based (6 of 42), and it ranks #4,260 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)

42 Around the middle fewer violations than 48% 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

Chehalis Water Department 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 Chehalis Water Department. 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
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
Chehalis Water Department: 42 violations, 14% health-based (this system)
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. 0 of 29 samples detected PFAS.

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

Population served record for Chehalis Water Department

EPA SDWIS lists 11,426 people served and 3,853 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.

EPA SDWIS · PWS WA5312250 WA primacy agency

Sources: EPA SDWIS · Washington State Department of Health, Office of Drinking Water

Nationwide peers

42 violations · 11,426 served: nearest cross-state SDWIS matches.

Cross-state systems near this violation count

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 Chehalis Water Department

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

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