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Community Water System · PWS ID5420030

Hollister City Of

Hollister, Idaho 83301 - drinking water served from groundwater sources to 220 people, tracked in EPA SDWIS and UCMR5.

220
People served
107
EPA violations
14
Health-based
Untested
UCMR5 result

The verdict

EPA records 107 drinking-water violations at Hollister City Of, 13% of them health-based - above the Idaho per-system average.

107
Total EPA violations on record
13%
Health-based (MCL / treatment failure)
220
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Hollister City Of

Hollister City Of is a local-owned community water system that delivers drinking water to 220 residents in Hollister, Idaho (Twin Falls County) through 120 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 107 total violations for this system , of which 14 (13%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 89 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Gross Alpha, Excl. Radon and U, recorded in 27 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

Across Idaho, EPA tracks 2,005 public water systems serving 1,743,912 people, with 104,850 cumulative violations and 19,965 health-based violations on record. About 96% of systems in the state carry at least one violation, and state-wide the average per system is 52.3 violations. Statewide, 40 of 60 UCMR5-tested systems have reported PFAS detections (66.7%).

Hollister City Of's 107 violations sit above the Idaho 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
220
Total Violations
107
Health-Based Violations
14
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
120
County
Twin Falls
School/Daycare
No
MCL Violations
14
Monitoring Violations
89
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Gross Alpha, Excl. Radon and U MR 27 2013
Chlorine MR 23 2025
Coliform (TCR) MR 19 2012
Coliform (TCR) MCL 9 2014
TTHM MR 6 2012
Total Haloacetic Acids (HAA5) MR 6 2012
Nitrate MR 4 2015
Gross Alpha, Excl. Radon and U MCL 4 2008
Radium-228 MR 2 2012
Revised Total Coliform Rule MON 2 2025
Consumer Confidence Rule Other 2 1999
TTHM MCL 1 2005
Public Notice Other 1 2011

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 Hollister City Of.

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 ID5420030 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Idaho Drinking Water Authority

Idaho'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 ID 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
2025 Chlorine MR 23 SDWIS / ID5420030 / 0999
2025 Revised Total Coliform Rule MON 2 SDWIS / ID5420030 / 8000
2015 Nitrate MR 4 SDWIS / ID5420030 / 1040
2014 Coliform (TCR) MCL 9 SDWIS / ID5420030 / 3100
2013 Gross Alpha, Excl. Radon and U MR 27 SDWIS / ID5420030 / 4000
2012 Coliform (TCR) MR 19 SDWIS / ID5420030 / 3100
2012 TTHM MR 6 SDWIS / ID5420030 / 2950
2012 Total Haloacetic Acids (HAA5) MR 6 SDWIS / ID5420030 / 2456
2012 Radium-228 MR 2 SDWIS / ID5420030 / 4030
2011 Public Notice Other 1 SDWIS / ID5420030 / 7500
2008 Gross Alpha, Excl. Radon and U MCL 4 SDWIS / ID5420030 / 4000
2005 TTHM MCL 1 SDWIS / ID5420030 / 2950
1999 Consumer Confidence Rule Other 2 SDWIS / ID5420030 / 7000

How Hollister City Of Compares

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

Metric Hollister City Of Idaho avg Federal benchmark
Total violations 107 52.3 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 14 10 Indicates a contaminant exceeded a federal MCL
PFAS detection None 66.7% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 220 870 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,005 regulated public water systems in Idaho.

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 Hollister City Of water safe to drink? ▼
Hollister City Of (PWS ID: ID5420030) has 107 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 220 people using Groundwater sources.
How many people does Hollister City Of serve? ▼
Hollister City Of serves 220 people in Hollister, Idaho. It is a Local-owned system using Groundwater water sources with 120 service connections.
What type of violations does Hollister City Of have? ▼
Hollister City Of has 107 total violations: 14 health-based violations (MCL exceedances or treatment failures), 89 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Hollister City Of water? ▼
No PFAS testing data is available for Hollister City Of under the EPA's UCMR5 monitoring program.
What water source does Hollister City Of use? ▼
Hollister City Of uses Groundwater 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.