Washington County, Minnesota: septic system inspection at sale
Checked on November 9, 2026 against the official rule. Rule set by Washington 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 |
|---|---|
| What is required | County page: Compliance Inspections 'Required before selling or transferring a property with a septic system'; not required if inspection within 3 years or new system <5 yrs with certificate. Source: washingtoncountymn.gov |
| Triggered by | sale, transfer Source: washingtoncountymn.gov |
| Deadline | Before selling or transferring a property with a septic system Source: washingtoncountymn.gov |
| How long a report is valid | 3 years (inspection within 3 yrs satisfies) Source: washingtoncountymn.gov |
| Exemptions |
Source: washingtoncountymn.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: Washington County.
Checked on November 9, 2026: read on the official site.
Septic systems in Washington County: the state’s count
MPCA counts 19,984 septic systems (SSTS) in Washington County in 2025, the 8th highest number of Minnesota’s 87 counties. Licensed inspectors and the county did 434 compliance inspections of existing systems that year: 2.2% of the county’s systems, against 2.11% statewide (the 23rd highest share). The county issued 279 construction permits in 2025 and 6,448 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. The county figures include the city and township septic programs inside it (MPCA footnote).
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 Washington County
In 2015 about 47,417 of Washington County’s 251,597 residents (19%) got their drinking water from a private well, by the USGS estimate. That is the 71st highest share of the 87 Minnesota counties in the USGS table, and the 5th 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 94% of Washington County’s rated land “very limited” for a conventional septic drain field, 6% “somewhat limited” and 0% “not limited”, the 57th highest “very limited” share of 85 Minnesota counties with survey data. The most common limits: slow percolation (dense or clay soil) on 65%; fast seepage below the field (risk to groundwater) on 58%; steep slopes on 33%.
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 Washington 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 Washington County.
| Lab | Town | Distance | Certified on the list for |
|---|---|---|---|
| Pace Analytical Services, LLC - Minneapolis | Minneapolis, MN | 16 miles | coliform bacteria, nitrate, arsenic |
| Instrumental Research, Inc. | Fridley, MN | 20 miles | coliform bacteria, nitrate, arsenic (subcontracted) |
| EMSL Analytical, Inc. | New Hope, MN | 24 miles | coliform bacteria, nitrate, arsenic |
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 Washington 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 Washington County.
| Rule | State | Distance | Covers | Checked |
|---|---|---|---|---|
| Dakota County | Minnesota | about 19 miles | Septic system | November 9, 2026 |
| Dakota County | Minnesota | about 19 miles | Well water test | November 9, 2026 |
| Chisago County | Minnesota | about 33 miles | Septic system | November 9, 2026 |
| Goodhue County | Minnesota | about 42 miles | Septic system | November 9, 2026 |
| Isanti County | Minnesota | about 46 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.