Is Oskaloosa, KS 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 ↓
80.9/100
waterverge.com Oskaloosa, KS — Water Quality Report
Oskaloosa's drinking water received a grade of B+ (80.9 out of 100), indicating good water quality. The city's 2 water systems serve approximately 2,266 residents using groundwater.
Lead levels were measured at 0.0 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 25 violations on record, including 3 health-based violations. 11 remain unresolved.
What to know about Oskaloosa's water
Oskaloosa ranks #157 out of 323 cities in Kansas for water quality, placing it mid-range in the state.
Oskaloosa 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, Oskaloosa may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Oskaloosa, KS water safe to drink?
Oskaloosa's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (80.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 2,266 residents using groundwater (wells).
Recent water quality updates for Oskaloosa
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Oskaloosa's water quality assessment. Grade: B+ (80.9/100).
Contaminants: Total Haloacetic Acids (HAA5), TTHM.
Contaminants: Lead and Copper Rule.
Contaminants: Total Haloacetic Acids (HAA5), TTHM.
Federal disaster declaration (FEMA DR-3236). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-1000). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Oskaloosa'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
Oskaloosa's water system has 25 total violations on record, including 3 health-based violations. 11 remain unresolved. 2 violations were issued in the last 5 years.
Flood & environmental risk
Jefferson County has experienced 4 federally declared disasters since 1973. 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 Perry Lk Nr Perry, Delaware R.
Where does Oskaloosa's water come from?
Oskaloosa's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 2,266 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Perry Lk Nr Perry (lake), Delaware R (river).
What Oskaloosa residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Oskaloosa'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.
Oskaloosa'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
Flood & disaster history
Jefferson County has experienced 4 federally declared disasters since 1973. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Oskaloosa'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. | 0.0 | 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. | 2.10 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Oskaloosa compares by contaminant
Explore where Oskaloosa ranks among all Kansas cities for specific contaminants.
Water source & infrastructure
Where Oskaloosa's water comes from
Oskaloosa'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 2,266 people through 2 water systems.
Water bodies near Oskaloosa
Oskaloosa is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Oskaloosa
| System Name | PWSID | Population | Source |
|---|---|---|---|
| JEFFERSON CO RWD 7 | KS2008713 | 1,180 | GW |
| OSKALOOSA, CITY OF | KS2008714 | 1,086 | GWP |
How Oskaloosa compares
Full Kansas rankings →Oskaloosa's score of 80.9/100 is above the average of 62/100 among major Kansas cities. It outscores 8 of 10 nearby cities.
Nearby cities
View Kansas rankings →About Oskaloosa, KS
Wikipedia →Oskaloosa is a city in and the county seat of Jefferson County, Kansas, United States. As of the 2020 census, the population of the city was 1,110.
Learn more about your water
Guides and resources related to Oskaloosa's water quality findings.
Explore water quality across Jefferson
Frequently asked questions
Is Oskaloosa, KS tap water safe to drink?
Oskaloosa's water quality earned a grade of B+ (80.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #157 out of 323 cities tested in Kansas.
What contaminants are in Oskaloosa's water?
Lead was measured at 0.0 ppb (90th percentile). 25 violations are on record.
How is Oskaloosa'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 Oskaloosa?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Oskaloosa's water come from?
Oskaloosa's water is sourced from Groundwater. The city has 2 water systems serving approximately 2,266 residents.
What health violations has Oskaloosa's water system had?
Oskaloosa has 3 health-based violations on record. The most recent violation was recorded in January 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 11 violations remain unresolved.
Is Oskaloosa's groundwater at risk of contamination?
Oskaloosa 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 25 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 Oskaloosa's water compare to other cities?
Oskaloosa ranks #157 out of 323 cities in Kansas (better than 51% of state cities) and #7668 out of 15744 cities nationally (51th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.