Watonwan County septic services.

Watonwan County administers the only septic (SSTS) program in the county; MPCA's 2025 annual report lists no separate city or township program. Your permit runs under the county's own SSTS ordinance — required by Minn. Stat. § 115.55 and allowed to be stricter than the state rules — and the county must give you a written list of any differences from those rules on request (subd. 2(c)); ask before designing. The report lists the county among the 59 requiring a compliance inspection at property transfer: expect the system checked when you buy or sell.

The dominant constraint here is seasonal soil saturation close to the surface (93.6% of rated soils), followed by water standing on the surface (12.4%). NRCS's Minnesota-specific ratings put 90.4% of rated ground in the very or extremely limited classes for a conventional below-grade trench and 69.8% for a mound -- where the trench is out, a mound is usually the design that works.