Septic & well regulations in Washington County, MN
Washington County is located in the Twin Cities Metro region of Minnesota. Washington County has sandy outwash and river terrace soils along the St. Croix and Mississippi, rolling till with loam and clay loam soils through the center, and shallow sandstone and limestone bedrock exposed along the bluffs. Understanding local permit requirements and soil conditions is essential before installing, repairing, or inspecting a septic system.
Permits & Requirements
New Installation
Washington County has one of the metro's larger populations still served by individual septic systems, particularly in Denmark, May, Grant, and the townships along the St. Croix. A permit and an approved design by an MPCA-licensed designer are required before installation, with soil borings establishing three feet of unsaturated soil above saturated soil or bedrock. The Lower St. Croix National Scenic Riverway overlay adds setback, bluff, and screening requirements well beyond ordinary shoreland rules for properties near the river. Only MPCA-licensed installers may build the system, and the county inspects it before backfill.
Repair
Repair permits are required for tank replacement, drainfield replacement, and changes to effluent distribution. Washington County applies the state's 30-day deadline for imminent threats to public health and safety and the ten-month deadline for systems that fail to protect groundwater. On St. Croix bluff parcels a repair frequently requires relocating the system entirely, because the original location no longer meets current slope and setback standards. Where sewer has become available, connection is often the more economical route.
Inspection
Washington County requires a compliance inspection by an MPCA-licensed inspector at property transfer for parcels served by an SSTS and before building permits that add bedrooms or increase design flow. Certificates of compliance are valid three years on existing systems and five on new construction. Well testing matters here as well: parts of eastern Washington County have documented PFAS contamination in groundwater, and the county and MDH maintain a well testing and treatment program for affected areas.
Washington County Environmental Health
Washington County Public Health and Environment
Contact the county environmental health department for permit applications, soil evaluation scheduling, and regulatory questions.
Soil & Terrain Characteristics
Washington County has sandy outwash and river terrace soils along the St. Croix and Mississippi, rolling till with loam and clay loam soils through the center, and shallow sandstone and limestone bedrock exposed along the bluffs. The sandy areas percolate quickly but offer limited filtration over a shallow aquifer. Kettle lakes and wetlands in the northern moraine create localized high water tables.
County-Specific Considerations
PFAS contamination from historic industrial disposal has affected private and municipal wells across a large area of eastern Washington County, and homeowners in the affected zone should confirm their well's status through the county's drinking water program before assuming it is safe. St. Croix Riverway rules are among the strictest land use standards in Minnesota and govern both septic siting and building placement. Sewer availability continues to expand and is worth checking before funding a septic replacement.
Find Services in Washington County
Septic Pumping
Washington County
Septic Inspection
Washington County
Septic Installation
Washington County
Well Water Testing
Washington County
Well Pump Repair
Washington County
Well Drilling
Washington County
Emergency Services
Washington County
Water Treatment
Washington County
Drain Field Repair
Washington County
Septic to Sewer Conversion
Washington County
Aerobic Septic System
Washington County
Well Water Filtration
Washington County
PFAS Water Testing
Washington County
Related Resources
Septic Permits & Regulations in Washington County — FAQ
How much does a septic permit cost in Washington County, MN?
- Septic permit fees in Washington County vary by permit type. New installation permits typically cost $200–$500, while repair permits are usually $100–$300. Contact Washington County Public Health and Environment at (651) 430-6655 for current fee schedules.
How long does it take to get a septic permit in Washington County?
- The septic permit process in Washington County generally takes 2–6 weeks, depending on soil evaluation scheduling and application completeness. Soil evaluations must be performed by a licensed soil scientist before applying.
Do I need a soil evaluation for a septic permit in Washington County?
- Yes. Washington County requires a professional soil evaluation before issuing any septic permit. A licensed soil scientist evaluates soil type, depth, drainage, and water table levels to determine the appropriate septic system design.
Who handles septic inspections in Washington County, MN?
- Washington County Public Health and Environment oversees all septic system inspections in Washington County. Contact them at (651) 430-6655 to schedule an inspection or ask about requirements.
Can I install my own septic system in Washington County?
- Washington County requires septic system installation by licensed contractors. All installations must be permitted through Washington County Public Health and Environment and pass inspection before the system can be used.
Need Septic or Well Services in Washington County?
Get connected with local professionals who understand Washington County's regulations and soil conditions. Request a free quote today.
Find Providers