Marysville, WA Building Setbacks & Zoning: Lot Coverage Limits (2026)

The density table at Marysville Municipal Code § 22C.010.080(2) sets two separate caps for every residential lot: maximum building coverage and maximum impervious surface. Building coverage is limited to 40 percent of lot area in the NR-4.5, NR-6.5 and WR-R-6-18 zones, and to 50 percent in the R-12, R-18 and R-28 zones. Impervious surface, which includes driveways, patios and any other surface that prevents rainwater infiltration, is capped at 70 percent in R-12 and R-18, 75 percent in R-28, and 70 percent in WR-R-6-18; in the two NR zones the cap is 45 percent for most lots but rises to 50 percent under § 22C.010.090(6)(a) for subdivisions with complete land use applications filed on or after May 8, 2017, the effective date of Ordinance 3057.

Section 22C.010.090(6)(b) directs that building coverage and impervious surface for regional uses are set at the time of permit review, and that nonresidential uses sited in a residential zone must instead follow the standards in § 22C.010.250. Section 22C.010.100(2) narrows what counts toward the impervious total: turf, landscaping, natural vegetation, pedestrian walkways five feet wide or less, and surface water retention or detention facilities are all excluded from the calculation, so a homeowner is not penalized for planted areas or drainage infrastructure. A separate exception at § 22C.010.090(13) lets single-family and middle housing lots within the R-12 through R-28 and WR-R-6-18 zones opt into the NR-6.5 zone's dimensional package instead, which substitutes a 50 percent building coverage and 65 percent impervious coverage limit on a 4,000-square-foot minimum lot.