Is Clark Fork, ID Tap Water Safe to Drink?
Graded A- — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
88.5/100
waterverge.com Clark Fork, ID — Water Quality Report
Clark Fork's drinking water received a grade of A- (88.5 out of 100), indicating good water quality. The city's 1 water system serves approximately 730 residents using groundwater.
Lead levels were measured at 2.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 22 violations on record, including 3 health-based violations. 1 remains unresolved.
What to know about Clark Fork's water
Clark Fork ranks #32 out of 139 cities in Idaho for water quality, placing it above average in the state.
Clark Fork 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.
As a small community water system, Clark Fork may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Clark Fork, ID water safe to drink?
Clark Fork's tap water meets most EPA standards but has areas that warrant attention. With a grade of A- (88.5/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 730 residents using groundwater (wells).
Recent water quality updates for Clark Fork
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Clark Fork's water quality assessment. Grade: A- (88.5/100).
Contaminants: Chlorine.
Contaminants: Revised Total Coliform Rule, Chlorine.
Federal disaster declaration (FEMA DR-4313). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-1987). Flood event — may have impacted local water infrastructure.
Contaminants: Chlorine, Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Clark Fork's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Clark Fork's water system has 22 total violations on record, including 3 health-based violations. 1 remain unresolved. 3 violations were issued in the last 5 years.
Flood & environmental risk
Bonner County has experienced 4 federally declared disasters since 1974. 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 Clark Fork River Below Cabinet Gorge Dam, Lightning Creek.
Where does Clark Fork's water come from?
Clark Fork's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 730 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Clark Fork River Below Cabinet Gorge Dam (river), Lightning Creek (river).
What Clark Fork residents can do
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.
Clark Fork'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 droughtBonner 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
Bonner County has experienced 4 federally declared disasters since 1974. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Clark Fork'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. | 2.0 | 15 | ppb | Inorganic | Safe |
| 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. | 3.21 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Clark Fork compares by contaminant
Explore where Clark Fork ranks among all Idaho cities for specific contaminants.
Water source & infrastructure
Where Clark Fork's water comes from
Clark Fork'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 local government ownership and serves approximately 730 people through 1 water system.
Water bodies near Clark Fork
Clark Fork is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Clark Fork
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CLARK FORK CITY OF | ID1090018 | 730 | GW |
How Clark Fork compares
Full Idaho rankings →Clark Fork's score of 88.5/100 is above the average of 43/100 among major Idaho cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Idaho rankings →About Clark Fork, ID
Wikipedia →Clark Fork is a city in Bonner County, Idaho. The population was 513 at the time of the 2020 census.
Learn more about your water
Guides and resources related to Clark Fork's water quality findings.
Explore water quality across Bonner
Frequently asked questions
Is Clark Fork, ID tap water safe to drink?
Clark Fork's water quality earned a grade of A- (88.5/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #32 out of 139 cities tested in Idaho.
What contaminants are in Clark Fork's water?
Lead was measured at 2.0 ppb (90th percentile). 22 violations are on record.
How is Clark Fork'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 Clark Fork?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Clark Fork's water come from?
Clark Fork's water is sourced from Groundwater. The city has 1 water system serving approximately 730 residents.
What health violations has Clark Fork's water system had?
Clark Fork has 3 health-based violations on record. The most recent violation was recorded in December 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
Is Clark Fork's groundwater at risk of contamination?
Clark Fork 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 22 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 Clark Fork's water compare to other cities?
Clark Fork ranks #32 out of 139 cities in Idaho (better than 77% of state cities) and #3442 out of 15744 cities nationally (78th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Clark Fork's small water system affect quality?
Clark Fork's system serves approximately 730 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 22 violations on record.