Title 27 — ZONING Chapter 27.21 — TWO-UNIT San Mateo Zoning Code · 2026-06 edition · ingested 2026-07-06 · San Mateo Sections in this part Article I — TWO-UNIT DEVELOPMENT Article II — URBAN LOT SPLITS DEVELOPMENT RESIDENTIAL OVERLAY DISTRICT – R1 DISTRICTS ← Previous Chapter 27.19 — ACCESSORY DWELLING UNITS AND JUNIOR ACCESSORY DWELLING UNITS Next → Article I — TWO-UNIT DEVELOPMENT