Title 27 — ZONING Chapter 27.28 — DOWNTOWN San Mateo Zoning Code · 2026-06 edition · ingested 2026-07-06 · San Mateo In this part Article I — R4-D DISTRICT— MULTIPLE FAMILY DWELLINGS FOR DOWNTOWN (MEDIUM HIGH DENSITY) Article III — R6-D DISTRICT—MULTIPLEFAMILY DWELLINGS (HIGH DENSITY)