Is Hermosa, SD Tap Water Safe to Drink?
Graded B, with 9 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
77.5/100
waterverge.com Hermosa, SD — Water Quality Report
Hermosa's drinking water received a grade of B (77.5 out of 100), indicating good water quality. The city's 4 water systems serve approximately 663 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 70 violations on record, including 9 health-based violations. 9 remain unresolved.
What to know about Hermosa's water
Hermosa ranks #107 out of 141 cities in South Dakota for water quality, placing it among the lowest-rated in the state.
Hermosa 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, Hermosa may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 8 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Hermosa, SD water safe to drink?
Hermosa's drinking water has significant quality concerns based on EPA testing data. With a grade of B (77.5/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 4 water systems serve approximately 663 residents using groundwater (wells).
Recent water quality updates for Hermosa
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Hermosa's water quality assessment. Grade: B (77.5/100).
Contaminants: Public Notice.
Contaminants: Revised Total Coliform Rule.
1 health-based. Contaminants: Stage 1 Disinfectants and Disinfection Byproducts Rule.
Federal disaster declaration (FEMA DR-4463). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3234). Coastal Storm event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Hermosa's water supply.
Well within EPA limits.
Violation history
Hermosa's water system has 70 total violations on record, including 9 health-based violations. 9 remain unresolved. 8 violations were issued in the last 5 years.
Flood & environmental risk
Custer County has experienced 5 federally declared disasters since 1972. 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 Battle Creek, Precip.
Where does Hermosa's water come from?
Hermosa's drinking water comes from groundwater (wells), supplied by 4 water systems serving approximately 663 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Battle Creek (river), Precip (river).
What Hermosa residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Hermosa'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.
Hermosa'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
D3 — extreme droughtCuster County is currently in D3 (extreme 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
Custer County has experienced 5 federally declared disasters since 1972. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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 |
Lead level trend (90th percentile)
See how Hermosa compares by contaminant
Explore where Hermosa ranks among all South Dakota cities for specific contaminants.
Water source & infrastructure
Where Hermosa's water comes from
Hermosa'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 663 people through 4 water systems.
Water bodies near Hermosa
Hermosa is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Hermosa
| System Name | PWSID | Population | Source |
|---|---|---|---|
| HERMOSA-OLD SYSTEM | SD4600154 | 420 | GW |
| HERMOSA WATER USERS ASSOCIATION | SD4602180 | 108 | GW |
| HEARTLAND COUNTRY RANCHETTES | SD4602235 | 95 | GW |
| NORTH HERMOSA WUD | SD4600329 | 40 | GWP |
How Hermosa compares
Full South Dakota rankings →Hermosa's score of 77.5/100 is above the average of 66/100 among major South Dakota cities. It outscores 6 of 10 nearby cities.
Nearby cities
View South Dakota rankings →About Hermosa, SD
Learn more about your water
Guides and resources related to Hermosa's water quality findings.
Explore water quality across Custer
Frequently asked questions
Is Hermosa, SD tap water safe to drink?
Hermosa's water quality earned a grade of B (77.5/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #107 out of 141 cities tested in South Dakota.
What contaminants are in Hermosa's water?
Lead was measured at 2.0 ppb (90th percentile). 70 violations are on record.
How is Hermosa'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 Hermosa?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Hermosa's water come from?
Hermosa's water is sourced from Groundwater. The city has 4 water systems serving approximately 663 residents.
What health violations has Hermosa's water system had?
Hermosa has 9 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. 9 violations remain unresolved.
Is Hermosa's groundwater at risk of contamination?
Hermosa 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 70 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 Hermosa's water compare to other cities?
Hermosa ranks #107 out of 141 cities in South Dakota (better than 24% of state cities) and #8991 out of 15744 cities nationally (43th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.