Is St Maries, ID Tap Water Safe to Drink?
Graded B- — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
73.3/100
waterverge.com St Maries, ID — Water Quality Report
St Maries's drinking water received a grade of B- (73.3 out of 100), indicating fair water quality. The city's 5 water systems serve approximately 4,561 residents using surface water.
Lead levels were measured at 4.0 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 129 violations on record, including 17 health-based violations. 11 remain unresolved.
What to know about St Maries's water
St Maries ranks #70 out of 139 cities in Idaho for water quality, placing it mid-range in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
Water quality score
See methodology →Is St Maries, ID water safe to drink?
St Maries's drinking water has significant quality concerns based on EPA testing data. With a grade of B- (73.3/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 5 water systems serve approximately 4,561 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for St Maries
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into St Maries's water quality assessment. Grade: B- (73.3/100).
1 health-based. Contaminants: Arsenic.
Contaminants: Public Notice.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-4313). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3244). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for St Maries'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
St Maries's water system has 129 total violations on record, including 17 health-based violations. 11 remain unresolved. 2 violations were issued in the last 5 years.
Flood & environmental risk
Benewah County has experienced 4 federally declared disasters since 1964. 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 St Maries River Nr Santa, St Joe River.
Where does St Maries's water come from?
St Maries's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 5 water systems serving approximately 4,561 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include St Maries River Nr Santa (river), St Joe River (river).
What St Maries residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in St Maries'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.
St Maries'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 droughtBenewah 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
Benewah County has experienced 4 federally declared disasters since 1964. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in St Maries'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. | 4.0 | 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. | 1.74 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how St Maries compares by contaminant
Explore where St Maries ranks among all Idaho cities for specific contaminants.
Water source & infrastructure
Where St Maries's water comes from
St Maries's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 4,561 people through 5 water systems.
Water bodies near St Maries
St Maries is located near 2 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving St Maries
| System Name | PWSID | Population | Source |
|---|---|---|---|
| ST MARIES CITY OF | ID1050024 | 4,173 | SW |
| COTTONWOOD POINT WATER ASSN | ID1050008 | 151 | GW |
| EMIDA WATER AND SEWER ASSOCIATION | ID1050009 | 95 | GW |
| EVERGREEN TERRACE WATER ASSOCIATION | ID1050010 | 85 | GW |
| CASSANDRA HILLS OWNERS ASSN | ID1050004 | 57 | GW |
How St Maries compares
Full Idaho rankings →St Maries's score of 73.3/100 is above the average of 43/100 among major Idaho cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Idaho rankings →Learn more about your water
Guides and resources related to St Maries's water quality findings.
Explore water quality across Benewah
Frequently asked questions
Is St Maries, ID tap water safe to drink?
St Maries's water quality earned a grade of B- (73.3/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #70 out of 139 cities tested in Idaho.
What contaminants are in St Maries's water?
Lead was measured at 4.0 ppb (90th percentile). 129 violations are on record.
How is St Maries'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 St Maries?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does St Maries's water come from?
St Maries's water is sourced from Surface water. The city has 5 water systems serving approximately 4,561 residents.
What health violations has St Maries's water system had?
St Maries has 17 health-based violations on record. The most recent violation was recorded in April 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 11 violations remain unresolved.
How does St Maries's water compare to other cities?
St Maries ranks #70 out of 139 cities in Idaho (better than 50% of state cities) and #10101 out of 15744 cities nationally (36th percentile). The grade of B- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.