Railing Permits in Unincorporated Contra Costa County

By San Ramon Custom Railing · October 3, 2026 · 5 min read

Where to apply: DCD and the ePermits Center

The Department of Conservation and Development is at 30 Muir Road in Martinez. Its Application and Permit Center can be reached at 925-655-2700.

Applications are digital-only through the County's ePermits Center, which replaced paper submittals. The Lamorinda office closed on March 1, 2023, so there is no closer counter for Alamo or Diablo residents. In practice, that means clean PDF drawings, an online account and patience with comment cycles. We prepare the drawings and handle the uploads for our clients.

Because there is no paper option, small details matter: drawings should be legible at full size, each sheet labeled, and the guard and handrail details easy to find. Missing information is the most common reason a simple railing application goes back for another round.

The County exemption test

The County, like Dublin, Pleasanton and Walnut Creek, exempts a deck from a building permit only when all four conditions are true:

• It is 200 square feet or smaller.
• It is no more than 30 inches above grade.
• It is detached from the house.
• It does not serve the required exit door.

Miss any one and a permit is required. Most Alamo and Blackhawk decks are attached to the house, so they fail the test before height even comes up. A 30-inch drop is also where a guard becomes mandatory, at 42 inches tall with openings that stop a 4-inch sphere.

What County plan check looks for

County plan checkers review railing details against the same California Building Code and Residential Code numbers used everywhere else in the Tri-Valley. Expect them to look for:

• A 42-inch guard height wherever the surface is more than 30 inches above grade.
• Openings that stop a 4-inch sphere, with no more than a 6-inch sphere at the stair tread triangle.
• A graspable handrail 34 to 38 inches above the stair nosings.
• Post anchorage that resists the required loads, shown with bolt sizes and blocking.
• For glass, the panel type and the base shoe or standoff hardware.

Hillside decks in Alamo and Diablo often sit well above grade on long posts, so the inspector will look closely at how the guard posts tie into the deck framing. A clear detail up front avoids a correction notice later.

Railing work that usually needs a County permit

• A new or rebuilt attached deck, with its guards and stairs.
• Replacing the full guard on an elevated deck, balcony or exterior stair.
• Structural changes to an interior stair, including new handrails.
• Anything that changes how posts anchor to the structure.

Small repairs, such as replacing a few pickets or refinishing a rail, usually do not. Replacing more than about half of an existing guard is commonly treated as a replacement that must meet current code. Confirm with the County how that applies to your project before you start. Our deck and balcony railing projects include that check from the first visit.

Fire zones in the hills

The hills here carry some of the highest fire ratings in our service area. On state maps, Diablo and the west Alamo hills are State Responsibility Area (SRA) High, Las Trampas Wilderness is SRA Very High, and there is a Very High local-area pocket on Blackhawk's north side. Check your parcel on the State Fire Marshal map viewer at osfm.fire.ca.gov/fhsz.

Chapter 7A wildfire construction rules apply to new homes in SRA zones and in Very High local zones; remodels and additions to existing homes are generally exempt. In the 2025 code cycle those rules moved into a new California Wildland-Urban Interface Code, and how it applies to some parcels is still being worked out, so confirm with the County. Either way, a noncombustible metal or glass railing is the sensible choice at the ember-catching edge of a hillside deck. See wrought iron and cable railing options.

HOA and district layers

County approval is often only one of the sign-offs you need. Blackhawk is a gated community with an active HOA. Diablo has been served by the Diablo Community Services District since 1969. Many associations in these areas require architectural review of exterior changes, including railings, and their rules can be stricter than the County's on color, profile and height. Confirm with your association before you file.

The order that works: association approval first, then the County permit, then fabrication. A single drawing set that satisfies both saves a round of revisions. Our Alamo, Blackhawk and Diablo railing page covers more local detail.

Timeline and how we help

Plan for association review, County plan check and fabrication to happen in sequence, not at once. We measure for free, draw the guard and handrail details, assemble the HOA package, upload to ePermits, answer plan-check comments and meet the County inspector at final. Fabrication waits until the permit is issued, so a plan-check revision never means cutting apart finished steel. If your project also touches a pool barrier, gate or exterior stair, we fold those details into the same drawing set so the County reviews everything once. Call (925) 438-6219 or request a free estimate online.