Public water system · WY5680092
ActiveYnp-Mammoth Hot Springs
At a glance
Ynp-Mammoth Hot Springs (PWSID WY5680092) is an active community water system in Park County, Wyoming. It reports serving 2,600 people through 274 service connections. Its primary water source is surface water, and EPA lists it as owned by the federal government. EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in August 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
2,600
Service connections
274
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Ynp-Mammoth Hot Springs compare with other water systems in Park County?
By EPA's size categories, Ynp-Mammoth Hot Springs is a small system (501 to 3,300 people). Park County has 49 active public water systems, and Ynp-Mammoth Hot Springs is the 5th-largest of them by population served. Its population served is about 3.3 times the county average of 777 people per system, and accounts for 6.8% of the 38,068 people reported by systems filed under the county. Across Wyoming, the 775 active systems average 838 people each. Nationally, the average active community water system reports serving 6,703 people, so Ynp-Mammoth Hot Springs is about 61% 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. Wyoming has 332 active community water systems, 43% of the state's 775 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 50 Wyoming systems (6.5%) list surface water as their primary source.
Who owns and regulates Ynp-Mammoth Hot Springs?
EPA lists Ynp-Mammoth Hot Springs as owned by the federal government. The WY state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 14 of the 49 active systems in Park County (29%) are also owned by the federal government.
Does Ynp-Mammoth Hot Springs have drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in August 2023. The violations listed here began between June 1980 and August 2023. By type: 8 monitoring and reporting and 1 required treatment not met. The contaminant or rule involved most often is Surface Water Treatment Rule (2 of them). EPA lists 6 as resolved and 3 as archived. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2023-08-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Surface Water Treatment Rulecode 0200 | No | Resolved |
| 2017-06-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2017-06-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2013-09-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2005-07-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Carbon, totalcode 2920 | No | Resolved |
| 1993-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Archived |
| 1980-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | No | Archived |
| 1980-06-24 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 9 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.
Ynp-Mammoth Hot Springs: frequently asked questions
Who runs Ynp-Mammoth Hot Springs?
Ynp-Mammoth Hot Springs (PWSID WY5680092) is a community water system owned by the federal government. It is regulated by the WY state drinking water program.
How many people does Ynp-Mammoth Hot Springs serve?
Ynp-Mammoth Hot Springs reports serving 2,600 people through 274 service connections in Park County, Wyoming.
Where does Ynp-Mammoth Hot Springs get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Ynp-Mammoth Hot Springs have any drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in August 2023. 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 Ynp-Mammoth Hot Springs' 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. EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in August 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the WY state drinking water program.
Where can I find Ynp-Mammoth Hot Springs' water quality report?
As a community water system, Ynp-Mammoth Hot Springs 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 Park County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Cody, City of | Park | 10,224 | Community | Purchased surface water |
| Northwest Rural Water District | Park | 7,330 | Community | Purchased surface water |
| Powell, City of | Park | 6,310 | Community | Purchased surface water |
| Ynp-Canyon Village | Park | 4,300 | Non-transient non-community | Surface water |
| Ynp-Norris | Park + 1 more | 1,515 | Transient non-community | Surface water |
| K Bar Z Guest Ranch | Park | 847 | 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, “Ynp-Mammoth Hot Springs, PWSID WY5680092, Wyoming”, https://aquacensus.com/water-systems/wyoming/ynp-mammoth-hot-springs-wy5680092 (data as of October 1, 2026).