Is Merrimac, WI Tap Water Safe to Drink?
Graded B+, with 14 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
80.3/100
waterverge.com Merrimac, WI — Water Quality Report
Merrimac's drinking water received a grade of B+ (80.3 out of 100), indicating good water quality. The city's 3 water systems serve approximately 547 residents using groundwater.
Lead levels were measured at 0.5 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 55 violations on record, including 6 health-based violations. 14 remain unresolved.
What to know about Merrimac's water
Merrimac ranks #259 out of 446 cities in Wisconsin for water quality, placing it below average in the state.
Merrimac 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, Merrimac may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Merrimac, WI water safe to drink?
Merrimac's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (80.3/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 547 residents using groundwater (wells).
Recent water quality updates for Merrimac
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Merrimac's water quality assessment. Grade: B+ (80.3/100).
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS, Public Notice.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-4402). Flood event — may have impacted local water infrastructure.
1 health-based. Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Merrimac's water supply.
Well within EPA limits.
Violation history
Merrimac's water system has 55 total violations on record, including 6 health-based violations. 14 remain unresolved. 3 violations were issued in the last 5 years.
Flood & environmental risk
Sauk County has experienced 4 federally declared disasters since 1976. 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 Devils Lake, Baraboo River.
Where does Merrimac's water come from?
Merrimac's drinking water comes from groundwater (wells), supplied by 3 water systems serving approximately 547 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Devils Lake (lake), Baraboo River (river).
What Merrimac residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Merrimac'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.
Merrimac'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 Merrimac
Industrial polluters nearby
Reported releases to surface water by facilities near Merrimac, ranked by pounds discharged annually.
Total reported releases to surface water: 88 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
MILWAUKEE VALVE CO LLC PRAIRIE DU SAC, WI53578 | Copper | 88 | 7.4 mi |
COATING PLACE INC. SAUK CITY SAUK CITY, WI53583 | — | — | 9.0 mi |
SENECA FOODS CORP BARABOO, WI53913 | — | — | 8.8 mi |
CUSTOM PULTRUSIONS INC. BARABOO, WI53913 | — | — | 7.4 mi |
TEEL PIPE LLC BARABOO, WI53913 | — | — | 9.2 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Sauk County has experienced 4 federally declared disasters since 1976. 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. | 0.5 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Merrimac compares by contaminant
Explore where Merrimac ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Merrimac's water comes from
Merrimac'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 547 people through 3 water systems.
Water bodies near Merrimac
Merrimac is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Merrimac
| System Name | PWSID | Population | Source |
|---|---|---|---|
| MERRIMAC WATERWORKS | WI1570093 | 440 | GW |
| SUMMER OAKS CONDO ASSOC | WI1570748 | 70 | GW |
| MERRIMAC ESTATES MHP | WI1570094 | 37 | GW |
How Merrimac compares
Full Wisconsin rankings →Merrimac's score of 80.3/100 is above the average of 65/100 among major Wisconsin cities. It outscores 7 of 10 nearby cities.
Nearby cities
View Wisconsin rankings →About Merrimac, WI
Wikipedia →Merrimac is a village in Sauk County, Wisconsin, United States, northwest of Madison. The population was 527 at the 2020 census. The village is located within the Town of Merrimac.
Learn more about your water
Guides and resources related to Merrimac's water quality findings.
Explore water quality across Sauk
Frequently asked questions
Is Merrimac, WI tap water safe to drink?
Merrimac's water quality earned a grade of B+ (80.3/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #259 out of 446 cities tested in Wisconsin.
What contaminants are in Merrimac's water?
Lead was measured at 0.5 ppb (90th percentile). 55 violations are on record.
How is Merrimac'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 Merrimac?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Merrimac's water come from?
Merrimac's water is sourced from Groundwater. The city has 3 water systems serving approximately 547 residents.
What health violations has Merrimac's water system had?
Merrimac has 6 health-based violations on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 14 violations remain unresolved.
Is Merrimac's groundwater at risk of contamination?
Merrimac 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 55 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 Merrimac's water compare to other cities?
Merrimac ranks #259 out of 446 cities in Wisconsin (better than 42% of state cities) and #7939 out of 15744 cities nationally (50th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.