Public water system · ID5160012
ActiveDeclo City of
At a glance
City of Declo (PWSID ID5160012) is an active community water system in Cassia County, Idaho. It reports serving 300 people through 135 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
300
Service connections
135
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Declo compare with other water systems in Cassia County?
By EPA's size categories, City of Declo is a very small system (500 people or fewer). Cassia County has 49 active public water systems. Its population served is about 22% below the county average of 387 people per system, and accounts for 1.6% of the 18,963 people reported by systems filed under the county. Across Idaho, the 1,961 active systems average 899 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Declo is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Idaho has 765 active community water systems, 39% of the state's 1,961 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,861 Idaho systems (95%) list groundwater as their primary source.
Who owns and regulates City of Declo?
EPA lists City of Declo as owned by a local government. The ID state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 5 of the 49 active systems in Cassia County (10%) are also owned by a local government.
Does City of Declo have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2025. The violations listed here began between October 1996 and July 2025. By type: 10 monitoring and reporting, 1 reporting and 1 required treatment not met. The contaminant or rule involved most often is Nitrate (3 of them). EPA lists 7 as resolved, 4 as archived and 1 as unaddressed. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-07-02 | ReportingNotification, Known or Potential LSL · code 4H | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2016-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Archived |
| 2016-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Archived |
| 2014-08-09 | Required treatment not metFailure To Address Deficiency · code 45 | Groundwater Rulecode 0700 | Yes | Resolved |
| 2010-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2004-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1998-01-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1997-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1997-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1997-01-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1996-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
City of Declo: frequently asked questions
Who runs City of Declo?
City of Declo (PWSID ID5160012) is a community water system owned by a local government. It is regulated by the ID state drinking water program.
How many people does City of Declo serve?
City of Declo reports serving 300 people through 135 service connections in Cassia County, Idaho.
Where does City of Declo get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does City of Declo have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is City of Declo's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the ID state drinking water program.
Where can I find City of Declo's water quality report?
As a community water system, City of Declo must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Cassia County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Burley Water Dept | Cassia | 10,345 | Community | Groundwater |
| Oakley City of | Cassia | 821 | Community | Groundwater |
| LDS Church Unity #5038650 | Cassia | 525 | Transient non-community | Groundwater |
| Oakley Valley Water Corporation | Cassia | 500 | Community | Groundwater |
| Itd Cotterell P O E | Cassia | 450 | Transient non-community | Groundwater |
| Malta Schools | Cassia | 440 | Non-transient non-community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Declo City of, PWSID ID5160012, Idaho”, https://aquacensus.com/water-systems/idaho/declo-city-of-id5160012 (data as of October 1, 2026).