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

Shoreline regulates how much of a residential lot can be covered in pavement, driveways, patios and other impervious surface through the 'Max. Hardscape' row of Table 20.50.020(1) in SMC § 20.50.020, the Development Code's core dimensional-standards table for the NR3, NR2, NR1 and TC-4 zones. The base hardscape ceiling is 50 percent of the lot in NR3, NR2 and NR1, and 90 percent in the TC-4 zone, well above the residential figure because TC-4 is built around building-bulk limits rather than yard space. Footnote (6) to the table lets that residential 50 percent ceiling rise when a lot holds more than one dwelling unit: NR2 lots increase to 60 percent hardscape and NR1 lots to 75 percent hardscape once two or more units share the lot, while NR3 stays fixed at 50 percent regardless of unit count.

The table separately tracks 'Max. Building Coverage,' the footprint occupied by buildings themselves, which the table marks N/A for the mixed-use residential zones because those zones are controlled by height and hardscape limits instead. Hardscape calculations interact with the unit-density and setback figures in the same table, and with the tree-conservation and stormwater standards administered under Chapters 20.50 and 13.10 SMC, since impervious surface drives the surface-water runoff Shoreline's Surface Water Utility manages. Planning and Community Development checks proposed hardscape against the table at building-permit review, and exceeding the applicable percentage without qualifying under footnote (6) is a Code Violation enforceable under the notice-and-order process of SMC § 20.30.760.