Sauk County, WI Water Use Rules: Recycled Water Rules (2026)

Sauk County's stormwater ordinance, Chapter 51 of the County Code, does not run a municipal recycled-water utility; the county's only rule touching reused water is the infiltration credit in Sec. 51.17(4), inside the Subchapter IV stormwater control performance standards. That subsection provides that where alternate uses of runoff are employed, such as for toilet flushing, laundry or irrigation, or storage on green roofs where an equivalent portion of the runoff is captured permanently by rooftop vegetation, the alternate use gets equal credit toward the infiltration volume the site otherwise must achieve.

The infiltration volume itself is set by Sec. 51.17(3): a site with up to 40 percent connected impervious surface must infiltrate at least 90 percent of its pre-development infiltration volume, a site between 40 and 80 percent impervious must hit 75 percent, and a site over 80 percent impervious must hit 60 percent, all measured against average annual rainfall. A developer who plumbs captured roof or site runoff back into toilets, laundry or irrigation, instead of routing it to a separate infiltration basin, can apply that reused volume toward those same percentages rather than building additional infiltration area.

The credit is administered as part of the Sec. 51.16 stormwater management plan review by the Zoning Administrator in the Department of Land Resources and Environment, and it applies only to sites that already trigger a Chapter 51 land use permit, meaning one acre or more of disturbance or 20,000 square feet of added impervious surface.