Portola — Overlay Districts

Last reviewed: July 2, 2026

Overview

Portola’s overlay and special-purpose districts add site- or area-specific rules on top of the city’s base zoning. They do not create new base uses; instead they modify how the underlying zone’s standards and approvals apply (for example, parking allowances or flood-plain controls). The city identifies overlays on the official zoning map (see development standards and map rules) and the overlay rules prevail where they conflict with the underlying zone. § 17.28.010

Note on links used in this page: the first natural mention of related implementation topics is hyperlinked for quick local guidance — parking, development standards, design review, ADUs, Title 24, variances, nonconforming uses, and signage.

How to read this page

• Each district subsection is Portola-specific (naming the local overlay code symbol used in the ordinance).
• Every requirement and practical point below is tied to the Portola code and shows the controlling section (§).
• Where the ordinance text is silent, the page flags “Not found in retrieved materials.”

Overlay districts: district-by-district

Floodplain (FP)

• Purpose: The FP overlay is intended to reduce flood risk, restrict hazardous uses in flood areas, and protect floodplain functions. § 17.28.020.A
• Typical permitted uses: Low‑impact, non-structural uses such as agriculture, parking, recreation, and accessory uses with low flood damage potential are allowed; structures and uses that increase flood heights or obstruct flows are either prohibited or require a flood encroachment permit. See the list of allowed uses and flood‑encroachment permit rules in § 17.28.020.F–G and the flood chapter provisions incorporated by reference. § 17.28.020.F–G
• Key standards/process triggers:
  • Any use involving structures, fill, or stored materials may require a flood encroachment permit; the ordinance treats FP regulations as additive to other zone rules and as controlling in a conflict. § 17.28.020.E–G
  • The FP limits “human habitation” on closed landfills and imposes elevation, anchoring, and floodproofing requirements through the flood chapter. See flood chapter cross-references for elevation and variance rules. § 17.47.030
• Where it applies: Areas of special flood hazard as shown on the adopted FEMA maps and the city’s official “Official Floodplain Maps” on file at City Hall. § 17.28.020.C

Old Town (OT)

• Purpose: The OT overlay targets parcels in Portola’s historic “old town” area and recognizes narrow lots/streets and historically important structures; intended to allow different parking expectations and area-specific design considerations. § 17.28.030.A–B
• Typical permitted uses: Uses are those of the underlying zoning district — the overlay does not list new base uses. § 17.28.030.E
• Key standards:
  • Underlying district standards apply, but where the OT overlay conflicts with other Title 17 provisions, the overlay governs. § 17.28.030.D
  • For most principally permitted uses in historic areas, the code allows operation without providing additional off‑street parking (exceptions apply for community assembly, colleges/universities, and new discretionary uses). See the local parking rules and the parking reduction pathway. § 17.40.030.D and § 17.28.030.A–E
• Where it applies: Parcels designated as Old Town (OT) on the official zoning map. § 17.28.030.C

Downtown Core (DC)

• Purpose: The DC overlay addresses parcels along Highway 70 and allows focused design standards and targeted parking rules for a downtown core. § 17.28.040.A
• Typical permitted uses: The uses of the underlying zoning district apply. § 17.28.040.E
• Key standards:
  • Underlying standards apply unless in conflict; the DC overlay may be used to modify parking requirements and apply downtown-specific design guidance. § 17.28.040.D
  • Like OT, principally permitted uses in the downtown core are often allowed without additional off‑street parking, with exceptions. Refer to local parking standards and administrative reduction options. § 17.40.030.D
• Where it applies: Parcels mapped as Downtown Core (DC) on the official zoning map. § 17.28.040.C

Landfill (LF)

• Purpose: The LF overlay controls landfill operations to avoid health/safety impacts such as noise, litter, and erosion. § 17.28.050.A–B
• Typical permitted uses: Operation of a Class II sanitary landfill is explicitly allowed, subject to required operational controls and conditions. § 17.28.050.D.1
• Key standards and conditions:
  • Hours: no operation between 7:00 p.m. and 7:30 a.m. (local operational hour restriction). § 17.28.050.D.1.a
  • Dust and litter controls: working face confinement, cover requirements, erosion control plan required. § 17.28.050.D.1.b–d
  • After closure: site must be covered, compacted, revegetated; permitted future uses exclude human habitation and favor non‑sensitive uses (agriculture, forestry, recreation, storage). § 17.28.050.E–F
• Where it applies: Parcels designated LF on the official zoning map. § 17.28.050.C

Precise Plan (PP)

• Purpose: The PP overlay is a customizable overlay established by an approved precise plan to lock in yards, open space, parking, landscaping, and related physical development rules for a specific area or project. It is designed to ensure internal project compatibility and fit with adjoining development. § 17.28.060.A
• Typical permitted uses: Uses are those of the underlying zone(s) combined with the approved precise plan; approval of a precise plan can be treated as the equivalent of approval of required land use permits for uses shown on the plan. § 17.28.060.D
• Key standards set by the precise plan:
  • Yard requirements (front, rear, side) are as shown on the approved precise plan. § 17.28.060.E
  • Lot area/width/depth and lot coverage default to the underlying zone unless the precise plan requires variations for site peculiarities. § 17.28.060.F
  • Building height is governed by the underlying zone unless the precise plan specifies otherwise. § 17.28.060.G
• Administrative note: Proceedings to establish a precise plan may be initiated by the planning commission, city council, or the property owner. § 17.28.060.A

Wild and Scenic River (WSR)

• The code lists WSR as an overlay/special purpose zone in the zoning district list, but the ordinance text for a WSR overlay district was not included in the retrieved materials. The listing appears in the zone table. § 17.10.010.B
• Details such as permitted uses or special controls for WSR: Not found in retrieved materials.

Decision‑relevant table (quick reference)

Checklist

• Confirm the parcel is within an overlay on the City of Portola Zoning Map (verify at City Hall / zoning map). § 17.10.020
• Identify the underlying base zoning district and applicable development standards. § 17.28.010
• If in FP, determine flood zone on FEMA maps and whether a flood encroachment permit is required; prepare elevation/floodproofing documentation. § 17.28.020; § 17.47.030
• If in OT or DC, confirm whether your proposed use falls within the “exceptions” that still require off‑street parking (community assembly, college/university, or new discretionary uses) and consider a parking reduction request if justified. § 17.28.030.E; § 17.28.040.E; § 17.40.030.D
• If the parcel is in LF and any landfill activity is planned, assemble operational controls (hours, working face, cover, erosion control) and verify post‑closure land use restrictions. § 17.28.050.D–F
• For a PP overlay application: prepare the required precise plan (scaled, professional drawings, eight copies per code) showing yards, parking, signs, landscaping, and circulation. § 17.28.060; § 17.97.030; § 17.97.050
• Check whether your project needs design review, or whether a variance or map amendment is required; use the administrative interpretation or appeal paths if there is uncertainty. See design review, variances and exceptions, and director interpretation rules. § 17.07.030; Chapter 17.91

(Links in checklist: first mention of development standards, design review, variances are hyperlinked above.)

Risks & Ambiguities

Plain‑English Summary

Portola’s overlays (Floodplain, Old Town, Downtown Core, Landfill, Precise Plan, and a listed WSR) layer site-specific requirements on top of your base zone; they usually adopt the underlying permitted uses but change how standards like parking, setbacks, flood protections, and operations are applied — check the official zoning map and the specific overlay section in Title 17 to see what applies to your parcel. § 17.28.010; § 17.10.020

Source References

• Portola Zoning — Title 17, Article: Overlay and Special Purpose Zones — § 17.28.010 (purpose of overlays)
• Floodplain (FP) overlay — § 17.28.020 (purpose, permitted uses, flood encroachment) and Flood chapter § 17.47.030 (flood standards incorporated)
• Old Town (OT) overlay — § 17.28.030 (purpose, applicability, permitted uses)
• Downtown Core (DC) overlay — § 17.28.040 (purpose and parking guidance)
• Landfill (LF) overlay — § 17.28.050.D–F (operational conditions, closure rules)
• Precise Plan (PP) overlay — § 17.28.060.A–G and precise-plan permit specifics § 17.28.060.D–G
• Zoning map adoption and district listing (shows overlays) — § 17.10.020; § 17.10.010.B
• Parking rules for OT/DC and administrative parking reduction — § 17.40.030.D; parking design standards § 17.40.040
• Director interpretations and appeals (boundary/ambiguity resolution): § 17.07.030 (interpretations) and Chapter 17.91 (appeals)

For a human‑readable home base, see the Portola zoning & planning overview pages used on this site (internal navigation): Portola Zoning & Planning home and topic pages linked throughout the body above.

Retrieved passages

• Portola Zoning Code (section and) High relevance show source text
• Portola Zoning Code (section shall) High relevance show source text
• Portola Zoning Code (§ 2) High relevance show source text
• Portola Zoning Code (Title 17) High relevance show source text
• Portola Zoning Code (Chapter 17.28) Medium relevance show source text
• Portola Zoning Code (§ 2) Medium relevance show source text
• Portola Zoning Code (section and) Medium relevance show source text
• Portola Zoning Code (Chapter 17.51) Medium relevance show source text

Cited sections

• Portola Zoning — Title 17, Article: Overlay and Special Purpose Zones — **§ 17.28.010** (purpose of overlays) (Title 17)
• Floodplain (FP) overlay — **§ 17.28.020** (purpose, permitted uses, flood encroachment) and Flood chapter **§ 17.47.030** (flood standards incorporated) (§ 17.28.020)
• Old Town (OT) overlay — **§ 17.28.030** (purpose, applicability, permitted uses) (§ 17.28.030)
• Downtown Core (DC) overlay — **§ 17.28.040** (purpose and parking guidance) (§ 17.28.040)
• Landfill (LF) overlay — **§ 17.28.050.D–F** (operational conditions, closure rules) (§ 17.28.050.D)
• Precise Plan (PP) overlay — **§ 17.28.060.A–G** and precise-plan permit specifics **§ 17.28.060.D–G** (§ 17.28.060.A)
• Zoning map adoption and district listing (shows overlays) — **§ 17.10.020; § 17.10.010.B** (§ 17.10.020)
• Parking rules for OT/DC and administrative parking reduction — **§ 17.40.030.D**; parking design standards **§ 17.40.040** (§ 17.40.030.D)
• Director interpretations and appeals (boundary/ambiguity resolution): **§ 17.07.030** (interpretations) and Chapter **17.91** (appeals) (§ 17.07.030)
• Portola_ZoningCode.md

• Official Portola code library