Is Corwin Springs, MT Tap Water Safe to Drink?
Graded C+ — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
68.3/100
waterverge.com Corwin Springs, MT — Water Quality Report
Corwin Springs's drinking water received a grade of C+ (68.3 out of 100), indicating fair water quality. The city's 5 water systems serve approximately 700 residents using groundwater.
Lead levels were measured at 15.0 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 95 violations on record, including 18 health-based violations. 23 remain unresolved.
What to know about Corwin Springs's water
Corwin Springs ranks #58 out of 115 cities in Montana for water quality, placing it mid-range in the state.
Corwin Springs relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
As a small community water system, Corwin Springs may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Corwin Springs, MT water safe to drink?
Corwin Springs's drinking water has significant quality concerns based on EPA testing data. With a grade of C+ (68.3/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 5 water systems serve approximately 700 residents using groundwater (wells).
Recent water quality updates for Corwin Springs
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Corwin Springs's water quality assessment. Grade: C+ (68.3/100).
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-4726). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4655). Flood event — may have impacted local water infrastructure.
Contaminants: 2,4,5-TP, OXAMYL, Carbofuran.
Contaminants: Lead and Copper Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Corwin Springs's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Corwin Springs's water system has 95 total violations on record, including 18 health-based violations. 23 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
Park County has experienced 6 federally declared disasters since 2005. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Boiling River At Mammoth,Ynp, Gardner River Near Mammoth, Ynp, Yellowstone River At Corwin Springs.
Where does Corwin Springs's water come from?
Corwin Springs's drinking water comes from groundwater (wells), supplied by 5 water systems serving approximately 700 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Boiling River At Mammoth,Ynp (river), Gardner River Near Mammoth, Ynp (river), Yellowstone River At Corwin Springs (river).
What Corwin Springs residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Corwin Springs's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Corwin Springs's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D2 — severe droughtPark County is currently in D2 (severe drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Park County has experienced 6 federally declared disasters since 2005. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Corwin Springs's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 15.0 | 15 | ppb | Inorganic | Near Limit |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.40 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Corwin Springs compares by contaminant
Explore where Corwin Springs ranks among all Montana cities for specific contaminants.
Water source & infrastructure
Where Corwin Springs's water comes from
Corwin Springs's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 700 people through 5 water systems.
Water bodies near Corwin Springs
Corwin Springs is located near 3 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Corwin Springs
| System Name | PWSID | Population | Source |
|---|---|---|---|
| EAST GATE WORK CAMP | MT0003440 | 208 | GW |
| GOLDEN AGE VILLAGE | MT0003313 | 180 | GW |
| CINNABAR THE | MT0001557 | 175 | GW |
| RANCH HEADQUARTERS | MT0003199 | 85 | GW |
| SPHINX MOUNTAIN MB HM PK | MT0003755 | 52 | GW |
How Corwin Springs compares
Full Montana rankings →Corwin Springs's score of 68.3/100 is above the average of 45/100 among major Montana cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Montana rankings →About Corwin Springs, MT
Wikipedia →Gardiner is a census-designated place (CDP) in Park County, Montana, United States, along the 45th parallel. As of the 2020 census, the population of the community and nearby areas was 833.
Learn more about your water
Guides and resources related to Corwin Springs's water quality findings.
Explore water quality across Park
Frequently asked questions
Is Corwin Springs, MT tap water safe to drink?
Corwin Springs's water quality earned a grade of C+ (68.3/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #58 out of 115 cities tested in Montana.
What contaminants are in Corwin Springs's water?
Lead was measured at 15.0 ppb (90th percentile). 95 violations are on record.
How is Corwin Springs's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Corwin Springs?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Corwin Springs's water come from?
Corwin Springs's water is sourced from Groundwater. The city has 5 water systems serving approximately 700 residents.
What health violations has Corwin Springs's water system had?
Corwin Springs has 18 health-based violations on record. The most recent violation was recorded in December 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 23 violations remain unresolved.
Is Corwin Springs's groundwater at risk of contamination?
Corwin Springs uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 95 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Corwin Springs's water compare to other cities?
Corwin Springs ranks #58 out of 115 cities in Montana (better than 50% of state cities) and #11100 out of 15744 cities nationally (30th percentile). The grade of C+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.