Westminster, CO Building Setbacks & Zoning: Setback Rules (2026)

Section 11-4-5, the Density Schedule, sets minimum building setbacks for every zoning district except Planned Unit Development. The Minimum Front Setback for a principal building is 30 feet in RE, R1, RA, R2, B1, C1, C2, M1 and O1, but drops to 25 feet in R3, R4, and T1. Minimum interior side setbacks range from 5 feet (R1, RA, R2, R3, R4, T1) to 7 feet (RE), while B1 and C1 use an adjacency rule requiring the same setback as any adjoining residential district under footnote (b).

The minimum combined total of both side setbacks ranges from 12 feet in R2, R3, R4 and T1 up to 20 feet in RE. Corner-lot side setbacks facing a side street run 15 feet across every residential district, and reverse-corner-lot side setbacks climb to 30 feet in RE, R1, RA and R2, or 25 feet in R3, R4 and T1. The rear setback for a principal building is a uniform 20 feet in every residential district from RE through T1, and 30 feet in O1; commercial districts B1, C1 and C2 instead use footnote (c), 20 feet from the center of an alley or the rear lot line, whichever is less.

Section 11-4-5(B) lets the City Manager or a designee grant up to a 10-percent reduction in setback requirements (or increase in height limits) if the change would not significantly alter the site plan or harm adjoining properties. Section 11-4-6(D) adds refinements: architectural features like cornices and eaves may extend up to 4 feet into a setback, ground-level decks may extend into a setback entirely, and fire escapes may project up to 6 feet.