Is Merrimac, WI tap water safe?
The short answer
1 of the 3 utilities serving Merrimac has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Wisconsin’s records: Merrimac Waterworks.
Merrimac Waterworks, which serves the most people here, has 2 results above the health goal. The worst: Arsenic at 0.75 ppb, above the health goal. Health goals are stricter than legal limits and are not enforced.
The water from Merrimac Waterworks is very hard, typically 249 mg/L (14.5 grains per gallon). How Wisconsin’s water compares.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Merrimac’s ZIP codes, from EPA’s estimates.
- Open report
Merrimac Waterworks
Wisconsin · serves 440 people · under 100 in Merrimac
2 results above the health goal. The worst: Arsenic at 0.75 ppb, above the health goal. Hardness: very hard, typically 249 mg/L (14.5 grains per gallon).
2 health-based violations since 2016
- Open report
Merrimac Estates MHP
Wisconsin · serves 37 people · under 100 in Merrimac
1 result above the health goal. The worst: Lead at 0.54 ppb, above the health goal. Hardness: very hard, 297 mg/L (17.4 grains per gallon).
No health-based violations since 2016
- Open report
Summer Oaks Condo Assoc
Wisconsin · serves 70 people · lists Merrimac among the places it serves
1 result above the health goal. The worst: Uranium at 0.04 ppb, above the health goal. Hardness: very hard, typically 279 mg/L (16.3 grains per gallon).
No health-based violations since 2016
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in Merrimac Waterworks’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic, Lead
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic, Lead
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic, Lead
Water testing near Merrimac
The 3 labs Wisconsin certifies closest to Merrimac, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
CT Laboratories
Baraboo, WI · about 8 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts
Pure Water Labs, LLC
Reedsburg, WI · about 20 miles
Certified for bacteria
Pure Water Labs, LLC
Lodi, WI · about 20 miles
Certified for bacteria
Wisconsin State Laboratory of Hygiene: Well water test kits ordered by phone and shipped free; you pay to mail the sample back, and the lab bills you after testing. Tests run from bacteria alone to a homeowner package covering bacteria, nitrate, fluoride, metals, hardness, volatile organic compounds and atrazine. Bacteria is $35, nitrate $35, lead $38, and the homeowner package $450, as of July 1, 2026. Public Environmental and Water Testing Prices, Wisconsin State Laboratory of Hygiene.
All 156 certified labs for WisconsinZIP codes in Merrimac
Which ZIP codes are in Merrimac: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: Wisconsin DNR and DATCP, certified and approved drinking water laboratories; distances from the Census 2020 ZIP code tabulation area gazetteer.
Near Merrimac
Other towns in Columbia County with a page of their own.
What to do next
- Read Merrimac Waterworks’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- Filters for ArsenicRanked by certification and what they cost over five years.The best reverse osmosis systems, ranked
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water