Watonwan County, Minnesota: septic system inspection at sale
Checked on November 9, 2026 against the official rule. Rule set by Watonwan County.
General information, not legal advice. This is our summary of the official rule as we read it. The ordinance or code and the health department decide: confirm with them before you list, sign or close.
The rule
| Question | What the official text says |
|---|---|
| Triggered by | property transfer Source: pca.state.mn.us |
| How long a report is valid | State default: 3 years (existing system), 5 years (new/replacement); county text may differ Source: revisor.mn.gov |
| Who may inspect | Minnesota Pollution Control Agency (MPCA) licensing of SSTS businesses. official list (webapp.pca.state.mn.us) Source: webapp.pca.state.mn.us |
This is our summary of the official rule as we read it. The ordinance or code and the health department decide: confirm with them before you list, sign or close. Rule set by: Watonwan County.
Checked on November 9, 2026: listed on the official state roster; the county's own text not read yet.
Septic systems in Watonwan County: the state’s count
MPCA counts 1,321 septic systems (SSTS) in Watonwan County in 2025, the 79th highest number of Minnesota’s 87 counties. Licensed inspectors and the county did 23 compliance inspections of existing systems that year: 1.7% of the county’s systems, against 2.11% statewide (the 38th highest share). The county issued 27 construction permits in 2025 and 711 from 2002 to 2025. MPCA’s table marks the county as requiring a compliance inspection at property transfer, which matches the rule on this page.
Source: MPCA, 2025 Subsurface Sewage Treatment Systems Annual Report (April 2026), Appendix A, as reported by each county; ranks among the 87 counties in the table (1 = highest). MPCA counts all compliance inspections of existing systems, whatever the trigger (property transfer, building permit and others).
Private wells in Watonwan County
In 2015 about 1,822 of Watonwan County’s 10,952 residents (17%) got their drinking water from a private well, by the USGS estimate. That is the 74th highest share of the 87 Minnesota counties in the USGS table, and the 80th highest number of private-well users.
As we read it, this rule covers the septic system, not the well.
Source: USGS county water use 2015 (Dieter et al., 2018). Ranks count the Minnesota counties in the USGS table (1 = highest).
Soils and septic systems here
USDA soil surveys rate 96% of Watonwan County’s rated land “very limited” for a conventional septic drain field, 4% “somewhat limited” and 0% “not limited”, the 50th highest “very limited” share of 85 Minnesota counties with survey data. The most common limits: a high water table (saturated soil near the surface) on 94%; slow percolation (dense or clay soil) on 85%; fast seepage below the field (risk to groundwater) on 18%.
Where soils are limited, inspections more often find drain fields that sit in seasonally wet soil, and replacement systems are often mounds or other engineered designs. A county-wide rating, not a test of one lot: a site evaluation decides. Source: USDA NRCS Soil Survey Geographic Database (SSURGO), via Soil Data Access, rating “ENG - Septic Tank Absorption Fields”, read November 15, 2026.
Certified labs nearest to Watonwan County for a well water test
Labs on the Minnesota certified drinking-water list that the list marks as taking samples from homeowners or outside clients, certified for coliform bacteria, nearest first. All of them are outside Watonwan County.
| Lab | Town | Distance | Certified on the list for |
|---|---|---|---|
| Minnesota Valley Testing Laboratories, Inc. | New Ulm, MN | 23 miles | coliform bacteria, nitrate, arsenic |
| UC Laboratory | Janesville, MN | 46 miles | coliform bacteria, nitrate, arsenic (subcontracted) |
| Worthington Public Utilities Laboratory | Worthington, MN | 54 miles | coliform bacteria |
Source: MDH Accredited Labs in Minnesota Accepting Drinking Water Samples from Private Well Users (October 2026; read November 15, 2026). Straight-line distance from the centre of Watonwan County (the average of its Census ZIP-area points); “approx.” = lab placed at its ZIP centre. Call the lab first: lists do not say which household tests each lab takes or what it charges.
Nearest other sale-time rules
Buying or selling near a county line? These are the closest other local rules in our census to Watonwan County.
| Rule | State | Distance | Covers | Checked |
|---|---|---|---|---|
| Brown County | Minnesota | about 16 miles | Septic system | November 9, 2026 |
| Martin County | Minnesota | about 21 miles | Septic system | November 9, 2026 |
| Cottonwood County | Minnesota | about 27 miles | Septic system | November 9, 2026 |
| Nicollet County | Minnesota | about 30 miles | Septic system | November 9, 2026 |
| Blue Earth County | Minnesota | about 31 miles | Septic system | November 9, 2026 |
Straight-line distance between county centres (the average of each county’s Census ZIP-area points). Townships, villages and health districts are placed at the centre of their county.