Skip to the page
Santa Clarita Gate InstallationA referral service for metal gates

Slopes and retaining walls in Santa Clarita

Where the ground climbs, the fence and gate rules change.

If your driveway runs past a retaining wall or up a hill, this is the page for you. The city's walls and fences section, 17.57.070, has its own rules for both, and steeper lots move to the hillside section, 17.51.020.

First: is it a hillside lot?

Everything else depends on the average slope of the land. The retaining wall rules in 17.57.070(G) apply where the average slope is under 10 percent. At 10 percent or more, walls go to the hillside development section instead, and the lot qualifies for hillside plan review (17.51.020(C)(1)). The hillside section also has the average slope worked out on development plans certified by a California licensed engineer.

On a hillside area, the same section bars excavation or other earth disturbance before a grading permit is issued. It is written for development review, so whether it reaches a single gate footing is a question for Planning, not something to assume.

Two slopes compared: 10 percent, a rise of 1 foot for every 10 feet across, and 3 to 1, a rise of 1 foot for every 3 feet across, about 33 percent 10 percent 1 ft up for every 10 ft across 3 to 1 1 ft up for every 3 ft, about 33 percent 10 ft 3 ft
Not to scale. 10 percent is the hillside line in 17.51.020; 3 to 1 is where the retaining wall permit exemption stops.

Cut wall or fill wall

On lots under 10 percent, the fence rules turn on which side of the wall the soil was moved. A cut wall holds back ground that was dug away; a fill wall holds up ground that was built up.

  1. Cut wall, your lot below. In a required yard, the wall can be topped by a fence as tall as that spot would allow if the wall were not there (17.57.070(G)(1)). Anywhere else, wall and fence together stay within the normal limits or the Director's call.
  2. Fill wall, your lot above. The wall can carry nothing more than an open, non-view-obscuring safety fence, 3 1/2 ft at the most (17.57.070(G)(2)).
  3. A taller fence near a fill wall. In a required yard it steps back 1 ft from the wall for every 1 ft of fence height, with planting kept between (17.57.070(G)(3)).
  4. Tall walls. A retaining wall over 6 ft, measured from the neighboring parcel, needs an adjustment (17.57.070(G)(4)).
Two cross sections. Left, a cut wall with the lot on the lower side and a fence on top. Right, a fill wall with the lot above, a short open safety fence on top, and a taller fence set back from the wall with planting between Fence on the wall 1 Your lot, lower side 2 3 4 Your lot, filled up
Cross sections, not to scale. Rules from 17.57.070(G).

Measuring a fence on a slope

The measuring point is whichever side of the fence or wall has the higher average ground, taken within 3 ft of it. To follow the ground, the top may rise and fall by up to 6 in, but the average can never go over the limit for that spot (17.57.070(H)). That is why a gate across a sloped drive can be built to step or rake with the ground.

When a wall needs a building permit

The city's building code waives the permit for a retaining wall up to 4 ft from the bottom of the footing to the top of the wall, or 30 in where it holds up a slope or a surcharge. Dry stacked block systems stop at 36 in above the lowest ground, or 18 in holding a slope. None of that applies on a slope steeper than 3 to 1 or in a floodplain (SCMC 18.02.030). Block or masonry pilasters over 42 in need a permit too.

What it means for a gate

  • The code writes its height limits for walls and fences, so plan a gate across the drive to the same street yard limit as the fence beside it, and ask Planning about the gate itself. Atop a fill wall, the fence stays short and open.
  • A slide gate parks on flat ground next to the opening; where a wall retains the drive, that flat ground can run out at the wall. The driveway gates page compares swing and slide.
  • Brick or block pillars for the gate need a building permit once they pass 42 in. Steel posts are not masonry.
  • Where a hillside project gets the city's design review, any fence facing a public road should look natural and match the land in color (17.51.020).
  • If an oak stands near the wall or the drive, its protected zone rules apply to any footing or trench as well.

Retaining wall questions

Does a retaining wall need a permit in Santa Clarita?

Not if it stays under the building code's limits: 4 ft from the bottom of the footing to the top, or 30 in when it holds up a slope or a surcharge, and it is not on a slope steeper than 3 to 1 or in a floodplain (SCMC 18.02.030). Above that, or with a fence planned on top, check with Building and Safety and Planning.

Can a fence go on top of a retaining wall?

Depends on the wall. On a cut wall with your lot on the lower side, the fence can be as tall as that spot allows without the wall. A fill wall takes only a see-through safety fence of 3 1/2 ft or less, and a taller fence has to set back 1 ft for each foot of height (17.57.070(G)).

How do I know if my lot is over 10 percent?

A 10 percent slope rises 1 ft for every 10 ft across. For the code, it is the average slope of the land, and the hillside section has it worked out on plans certified by a California licensed engineer, so Planning is the place to confirm it for your lot.

Gate going in beside a wall or up a slope? Mention it in your request.

Tell us about your gate