Building near the coast or a creek in Pasadena, California
Pasadena is inland, so its "near the water" rules cover the Arroyo Seco and flood-prone areas rather than a coastline. On mapped Arroyo Seco slope-bank lots, no structure may extend over or below the top edge of the slope bank, and any structure within 20 feet of that edge needs a Hillside Development Permit. In flood-prone areas, new construction and substantial improvements must be anchored and built with flood-resistant materials.
| Arroyo Seco slope bank | No structure over or below the top edge (mapped lots) [1] |
| Review buffer | Hillside Development Permit for any structure within 20 ft of the top edge [2] |
| 'Top edge' defined | Where natural slope drops at more than 50% [3] |
| Flood-prone areas | New construction and substantial improvements must be anchored and flood-resistant [4] |
| Substantial improvement | Work costing 50% or more of the structure's market value [5] |
| Floodplain compliance | Required for any structure built, extended, converted or altered [6] |
No coastal zone rules
The Pasadena code sections we reviewed contain no coastal-zone or Local Coastal Program provisions; the city's near-water rules protect the Arroyo Seco and manage flood-prone land.
Arroyo Seco slope bank
On lots shown on the Arroyo Seco Slope Bank Map (May 11, 2004), no structure may extend over or below the top edge of the slope bank [1]. The top edge is the highest existing grade where the natural slope drops away at more than 50%; you must provide a full topographic map to locate it [3]. Any structure within 20 feet of the top edge requires a Hillside Development Permit [2]. These rules are in the Hillside Overlay chapter, whose purposes include preserving riparian vegetation and natural streambeds to the maximum extent feasible. Where the Zoning Administrator finds a property may have riparian areas, wildlife corridors or protected trees, the project's CEQA review must analyze them and propose mitigation. Hillside lots also have a 35% lot-coverage cap.
Flood-prone areas
The Floodplain Management Regulations apply to all flood-prone areas in the city, identified by the floodplain administrator from federal, state and other flood data kept at the Planning & Community Development Department. No structure or land may be built, extended, converted or altered without complying [6]. In a flood-prone area, new construction and substantial improvements must be anchored against flotation, collapse and lateral movement and built with flood-resistant materials, with mechanical and electrical equipment designed or placed to keep water out [4]. A substantial improvement is work costing at least 50% of the building's pre-project market value [5]. The administrator also confirms other required state and federal permits are obtained.
Creeks and streams
Work in a stream bed or bank also needs state Fish and Wildlife notification (shown separately on this page). No separate citywide creek setback appeared in the sources reviewed.
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Next steps
- Check whether your lot is on the Arroyo Seco Slope Bank Map or in a Hillside Overlay (HD) district with the Planning Division.
- If building within 20 ft of the slope-bank top edge, commission a topographic survey and apply for a Hillside Development Permit.
- Ask the floodplain administrator at Planning & Community Development (175 N. Garfield Ave.) whether your site is flood-prone before designing new construction or a major remodel.
Common questions
- What are the building rules near the water in Pasadena, California?
- Pasadena is inland, so its rules cover the Arroyo Seco and flood-prone areas. On mapped slope-bank lots, no structure may extend over or below the top edge, and any structure within 20 feet of that edge needs a Hillside Development Permit.
- Do I need a permit to build near the Arroyo Seco in Pasadena, California?
- Yes, for any structure within 20 feet of the slope bank's top edge, you need a Hillside Development Permit. The top edge is where the natural slope drops at more than 50%.
- What are the flood rules for building in Pasadena, California?
- In flood-prone areas, new construction and substantial improvements must be anchored and built with flood-resistant materials. A substantial improvement is work costing 50% or more of the structure's market value.
California rules for building near the coast and creeks
California has no statewide shoreland setback. Near water, two state laws matter most.
The coastal zone (Coastal Act, Pub. Res. Code §30000 et seq.):
- Almost any development in the coastal zone needs a coastal development permit (CDP) (§30600). "Development" is broad: buildings, additions, grading, lot splits, removing major vegetation, and changes in intensity of use (§30106).
- The zone generally runs about 1,000 yards inland from mean high tide (up to 5 miles in some habitat areas, less in some cities). San Francisco Bay is excluded; BCDC regulates it (§30103).
- Where a city or county has a Local Coastal Program (LCP) certified by the Coastal Commission, it issues the CDP (§30519). Otherwise the Commission does.
- Local approvals can be appealed to the Coastal Commission for projects between the sea and the first public road, within 300 ft of a beach or the mean high tide line, within 100 ft of a wetland, estuary or stream, or within 300 ft of a coastal bluff (§30603).
- Some improvements to existing homes and repairs are exempt (§30610), with exceptions set by regulation.
Creeks, streams and lakes statewide: you must notify the Department of Fish and Wildlife before work that diverts or blocks a stream, changes its bed, channel or bank, or puts material into it (Fish & Game Code §1602), even for streams that are dry part of the year. CDFW may require a Lake or Streambed Alteration Agreement.
Cities and counties often add their own creek setbacks or riparian buffers.
What the ordinance says
- Sec. 17.29.050.D, Zoning Code Chapter 17.29 - Hillside Overlay Districts (Arroyo Seco slope bank)
No structure shall extend over or below the top edge of the Arroyo Seco slope bank on a lot identified on the Arroyo Seco Slope Bank Map, dated May 11, 2004, a copy of which is maintained by the City Clerk.
- Sec. 17.29.050.D.2, Zoning Code Chapter 17.29 - Hillside Overlay Districts (Arroyo Seco slope bank)
A Hillside Development Permit shall be required for the development of any structure within 20 feet of the top edge.
- Sec. 17.29.050.D.1, Zoning Code Chapter 17.29 - Hillside Overlay Districts (Arroyo Seco slope bank)
The "top edge" of the Arroyo is the highest existing grade elevation at the point where the natural gradient inclines downward at a slope greater than 50 percent in the mapped area.
- Sec. 14.27.140, Municipal Code Chapter 14.27 - Floodplain Management Regulations, p. 1
If a proposed building site is in a flood-prone area, all new construction and substantial improvements, including manufactured homes, shall: A. Be designed (or modified) and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.
- Sec. 14.27.030 ("Substantial improvement"), Municipal Code Chapter 14.27 - Floodplain Management Regulations, p. 1
"Substantial improvement" means any reconstruction, rehabilitation, addition, or other proposed new development of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the "start of construction" of the improvement.
- Sec. 14.27.060, Municipal Code Chapter 14.27 - Floodplain Management Regulations, p. 1
No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the term of this chapter and other applicable regulations.