Is Walnut, IA Tap Water Safe to Drink?
Graded A, with 1 unresolved violation on record. See what was cited — and what it means for your tap. What to do next ↓
93/100
waterverge.com Walnut, IA — Water Quality Report
Walnut's drinking water received a grade of A (93 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 768 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 16 violations on record, including 10 health-based violations. 1 remains unresolved.
What to know about Walnut's water
Walnut ranks #77 out of 436 cities in Iowa for water quality, placing it above average in the state.
Walnut 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, Walnut may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Walnut, IA water safe to drink?
Walnut's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (93/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 768 residents using groundwater (wells).
Recent water quality updates for Walnut
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Walnut's water quality assessment. Grade: A (93/100).
Federal disaster declaration (FEMA DR-4421). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-1998). Flood event — may have impacted local water infrastructure.
Contaminants: Arsenic.
Contaminants: Coliform (TCR).
Contaminants: Combined Radium (-226 and -228).
Key contaminant findings
Based on the most recent EPA sampling data for Walnut's water supply.
Well within EPA limits.
Violation history
Walnut's water system has 16 total violations on record, including 10 health-based violations. 1 remain unresolved.
Flood & environmental risk
Pottawattamie County has experienced 8 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 West Nishnabotna River At Hancock, East Nishnabotna River Near Atlantic.
Where does Walnut's water come from?
Walnut's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 768 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include West Nishnabotna River At Hancock (river), East Nishnabotna River Near Atlantic (river).
What Walnut 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.
Walnut'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
Pottawattamie County has experienced 8 federally declared disasters since 1965. 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. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Walnut compares by contaminant
Explore where Walnut ranks among all Iowa cities for specific contaminants.
Water source & infrastructure
Where Walnut's water comes from
Walnut'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 768 people through 1 water system.
Water bodies near Walnut
Walnut is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Walnut
| System Name | PWSID | Population | Source |
|---|---|---|---|
| WALNUT MUNICIPAL UTILITIES | IA7872062 | 768 | GW |
How Walnut compares
Full Iowa rankings →Walnut's score of 93/100 is above the average of 72/100 among major Iowa cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Iowa rankings →About Walnut, IA
Learn more about your water
Guides and resources related to Walnut's water quality findings.
Explore water quality across Pottawattamie
Frequently asked questions
Is Walnut, IA tap water safe to drink?
Walnut's water quality earned a grade of A (93/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #77 out of 436 cities tested in Iowa.
What contaminants are in Walnut's water?
Lead was measured at 0.0 ppb (90th percentile). 16 violations are on record.
How is Walnut'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 Walnut?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Walnut's water come from?
Walnut's water is sourced from Groundwater. The city has 1 water system serving approximately 768 residents.
What health violations has Walnut's water system had?
Walnut has 10 health-based violations on record. The most recent violation was recorded in July 2001. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
Is Walnut's groundwater at risk of contamination?
Walnut 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 16 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 Walnut's water compare to other cities?
Walnut ranks #77 out of 436 cities in Iowa (better than 82% of state cities) and #1033 out of 15744 cities nationally (93th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Walnut's small water system affect quality?
Walnut's system serves approximately 768 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 16 violations on record.