Is Doon, IA 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 ↓
83.1/100
waterverge.com Doon, IA — Water Quality Report
Doon's drinking water received a grade of B+ (83.1 out of 100), indicating good water quality. The city's 2 water systems serve approximately 2,384 residents using groundwater.
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 69 violations on record, including 32 health-based violations. 2 remain unresolved.
What to know about Doon's water
Doon ranks #372 out of 436 cities in Iowa for water quality, placing it among the lowest-rated in the state.
Doon 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, Doon may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Doon, IA water safe to drink?
Doon's tap water meets most EPA standards but has areas that warrant attention. With a grade of B+ (83.1/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 2 water systems serve approximately 2,384 residents using groundwater (wells).
Recent water quality updates for Doon
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Doon's water quality assessment. Grade: B+ (83.1/100).
Contaminants: Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule.
Federal disaster declaration (FEMA DR-4421). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4184). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Doon'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
Doon's water system has 69 total violations on record, including 32 health-based violations. 2 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
Lyon County has experienced 7 federally declared disasters since 1965. 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 Rock River Below Tom Creek At Rock Rapids.
Where does Doon's water come from?
Doon's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 2,384 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Rock River Below Tom Creek At Rock Rapids (river).
What Doon 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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Doon'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
Top industrial polluters within 10 miles of Doon
Industrial polluters nearby
Reported releases to surface water by facilities near Doon, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
AGROPUR INC HULL, IA51239 | — | — | 8.2 mi |
VALLEY PLATING INC. ROCK VALLEY, IA51247 | — | — | 7.1 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Lyon County has experienced 7 federally declared disasters since 1965. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Doon'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. | 1.60 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Doon compares by contaminant
Explore where Doon ranks among all Iowa cities for specific contaminants.
Water source & infrastructure
Where Doon's water comes from
Doon'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 2,384 people through 2 water systems.
Water bodies near Doon
Doon is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Doon
| System Name | PWSID | Population | Source |
|---|---|---|---|
| LYON-SIOUX RWS-DOON | IA6000733 | 1,765 | GW |
| DOON WATER SUPPLY | IA6015047 | 619 | GWP |
How Doon compares
Full Iowa rankings →Doon's score of 83.1/100 is above the average of 72/100 among major Iowa cities. It outscores 8 of 10 nearby cities.
Nearby cities
View Iowa rankings →About Doon, IA
Wikipedia →Rock Rapids is a city in and the county seat of Lyon County, Iowa, United States. The population was 2,611 in the 2020 census, an increase from 2,573 in the 2000 census.
Learn more about your water
Guides and resources related to Doon's water quality findings.
Explore water quality across Lyon
Frequently asked questions
Is Doon, IA tap water safe to drink?
Doon's water quality earned a grade of B+ (83.1/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #372 out of 436 cities tested in Iowa.
What contaminants are in Doon's water?
Lead was measured at 4.0 ppb (90th percentile). 69 violations are on record.
How is Doon'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 Doon?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Doon's water come from?
Doon's water is sourced from Groundwater. The city has 2 water systems serving approximately 2,384 residents.
What health violations has Doon's water system had?
Doon has 32 health-based violations on record. The most recent violation was recorded in December 2022. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
Is Doon's groundwater at risk of contamination?
Doon 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 69 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 Doon's water compare to other cities?
Doon ranks #372 out of 436 cities in Iowa (better than 15% of state cities) and #6594 out of 15744 cities nationally (58th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.