Knoxville, TN Building Setbacks & Zoning: Lot Coverage Limits (2026)

Appendix B (the 2024 'Recode Knoxville' zoning ordinance) defines impervious surface coverage in Sec. H as 'a measure of intensity of land use that represents the portion of a site that is occupied by structures, pavement, and other impervious surfaces that do not allow for the absorption of water into the ground,' calculated as the percentage of impervious area against total lot area. A permeable pavement system is credited at only 50% impervious, subject to Department of Engineering approval, which rewards porous driveways and parking without waiving the underlying cap.

Table 4-2 in Sec. 3 sets the maximum impervious surface percentage separately for each of Knoxville's seven residential neighborhood districts: EN 35%, RN-1 40%, RN-2 40% (50% for nonresidential uses), RN-3 45% (60% for townhouses and nonresidential), RN-4 45% (60% for townhouses, multi-family and nonresidential), RN-5 45% (60% for townhouse, multi-family and nonresidential), RN-6 50% (70% for townhouse, multi-family and nonresidential), and RN-7 70% flat. The same table caps maximum building coverage separately and lower, from 25% in EN up to 50% in RN-7, so a lot can reach its impervious cap through driveways, patios and other paved surface even while under its building-coverage limit.

Both caps sit on top of the district's minimum lot area and setback rules in the same table, and any residential lot not served by sanitary sewer must carry at least 20,000 square feet of lot area under Sec. B.