El Cajon, CA Building Setbacks & Zoning: Lot Coverage Limits (2026)

110 sets the maximum share of a lot that structures may occupy, and unlike the height table, coverage climbs steadily with density. RS-40, the city's largest-lot single-family zone, is held to the tightest limit at 30%. Every other standard single-family zone, RS-20, RS-14, RS-9 and RS-6, is allowed 40% coverage despite their smaller minimum lot sizes. Multifamily zones climb further: RM-6000 matches the single-family zones at 40%, RM-4300 rises to 50%, RM-2500 and RM-2200 both reach 55%, and RM-1450, the densest standard multifamily zone, tops out at 60%.

RM-HR is capped lower, at 50%, even though it generally allows taller buildings and denser development than the other RM zones. 165. The coverage calculation is broader than just building footprints: the section specifically counts all covered structures, both primary and accessory, and it also pulls in overhead lattices and trellises that might otherwise be treated as open landscape features. 120 reinforces this by capping the combined floor area of all accessory and primary structures on a lot at the same percentage set by this table, so a homeowner cannot add a detached garage or workshop that pushes total coverage past the zone's limit even if the primary house alone stays under it.