Fence Rules in Atherton

It does not, and that is the first thing separating Atherton from the towns around it. The code sets six feet for a fence generally along all property lines, six feet again at the front lot line or along public streets, and six feet for interior fences and walls between neighbours (Table 17.46.030-1). There is no lower figure for a front yard, none for a side yard, and none for the street side of a corner lot.

Eight feet appears three times in that table, and each one is about a place rather than a permission to build taller:

• Along a lot line adjoining a public or private school, or the railroad right-of-way — eight feet.
• Coincident with the town boundary — eight feet, except where that boundary faces a street, and there it drops back to six (note 1).
• Along one of seven named streets — six or eight, measured two different ways. That has its own question below.

Atherton's front setback is large — sixty feet for a main building on an R-1A lot (§17.32.040) — but it is a building setback. It sets no fence height. That is the assumption that travels here from Menlo Park and Los Altos, where the low front-yard number lives in the setback, and arrives wrong.

The paperwork, and it changes it completely. Fences not over six feet, on private property and at least ten feet from the public right-of-way, are exempt from permit requirements (§17.46.020(C)(2)). Inside that ten-foot band the town's building department requires a building permit before construction, whatever the height.

So the same six-foot fence is two different jobs depending on where it stands. Ten feet in from the street it is exempt. Nine feet in, it is a permit.

Above six feet — and in that band the town allows up to eight — the fence must be shielded from public view by plants installed at the time of construction, and the species chosen has to reach the height of the fence within three years of planting (§17.46.030(C)(2)).

Seven, and the list is closed. On a lot adjoining El Camino Real, Marsh Road, Middlefield Road, Valparaiso Avenue, Alameda de la Pulgas, Bay Road or Ringwood Avenue, a fence may be built to six feet above the natural grade it stands on, or eight feet above the elevation of the centerline of the adjacent pavement — whichever is higher (Table 17.46.030-1, note 2).

Read the last three words before assuming the eight. Where the lot sits above the road, six feet from your own ground can already be the higher of the two and the eight buys nothing; where the lot sits below it, the eight is real. Everywhere else in town height is measured from the natural grade at the base of the fence (§17.46.030(B)).

Three feet — and this is the one place where the town's own two documents describe the same triangle differently. Both are quoted here, because the difference lands on the ground rather than on paper.

The code defines a clear visibility area as "a triangular area bounded on two sides by street lines extending a distance of thirty feet from any street corner measured along the curb, gutter, or edge of pavement" (§17.60.020). The town's fence handout describes instead "the 30 foot triangular area bounded by the two rights-of-way" (General Guidelines for Fences, Walls and Gates, rev. 12/8/2022).

A street line is the boundary between the street and your lot. A curb, a gutter and an edge of pavement are none of those, and on an Atherton frontage they can sit several feet apart. Which pair of lines bounds the triangle, and which line the thirty feet is stepped off along, decides where the triangle actually falls on your corner.

The handout also adds a rule the code does not contain: that fences at the corner of two rights-of-way, including gates, gate posts and columns, must be located at least thirty feet back from the corner intersection. The code requires no such setback. It limits height inside the area to three feet and says nothing about keeping the fence out of it.

So there is a question worth putting to the Planning Department in these words before a corner post is set: for this address, is the thirty feet measured along the curb or along the street line, and does the fence have to stand thirty feet back from the corner, or only stay under three feet inside the triangle?

One more thing changes inside the triangle. Height there is measured from the surface of the closest adjoining pavement, not from the natural grade used everywhere else on the lot (§17.46.030(B)). On a lot sitting above the road, a run you measured at three feet from your own ground is over three feet by the rule that applies there.

Three different things, and they are not alternatives to one another.

Zoning clearance is required for all fences, walls, entry gates, posts, decorative features and similar structures, filed with the town planner (§17.46.020(A)). The exemptions are three and that is the whole list (§17.46.020(C)): a wall supporting a permitted structure; fences not over six feet on private property and at least ten feet from the public right-of-way; and temporary fences around a construction site.

A building permit is required for any fence over six feet, for any fence within ten feet of the right-of-way, and for entry gates, posts and columns, which the town treats as accessory structures.

A special structure permit is required for retaining walls taller than six feet, or located less than twenty feet from other retaining walls on the same property; otherwise a retaining wall needs only a building permit (§17.46.020(B)).

They are structures in their own right, and the ceiling is ten feet: entry gates, posts and decorative features may exceed the table's heights up to ten feet on issuance of a building permit (§17.46.040).

The rest of that section is dimensional and easy to trip over:

• The width of posts and columns built into a fence or wall may not exceed thirty-three percent of the built height.
• The wall may transition from column height down to wall height over a length of no more than twenty feet.
• A light at the top of an entry gate post or column may not exceed eighteen inches; the post including its light may not exceed ten feet; and there may be no more than two lights per entrance.
• Keypads have to sit where a vehicle can reach them without encroaching into the street travel way.

The code does not answer that directly, and it is worth saying so plainly: chapter 17.46 sets no threshold at which a repair becomes new construction. What it does say is that fences and walls "shall be continuously maintained in an orderly and good condition, at no more than their maximum allowed height" (§17.46.050(A)), and that a fence maintained in violation of the title is a public nuisance subject to abatement (§17.46.050(B)).

What follows from that is a reading rather than a quotation, and we would rather name it as one: keeping a legally established fence in the condition and at the height it was cleared at is maintenance, and does not reopen the clearance. What is not maintenance is anything that changes what was cleared — a different height, a different position, or a run rebuilt past the six feet the exemption depends on. Where a job sits near that line, the town planner is the person who decides it, and asking costs less than abating.

Three measurements decide an Atherton fence, and only one of them is the fence.

How far the run stands from the right-of-way, because ten feet is the difference between an exempt fence and a permitted one. Which street it faces, because seven of them are measured from the crown of the road rather than from your ground. And where the corner triangle falls, because the town's two documents describe it differently and only Planning can say which applies at your address.

A boundary survey by a licensed surveyor is the only thing that fixes a property line for certain. Atherton Planning confirms what applies at a specific address, and the Building Department issues the permits.

We repair fences, posts and gates in Atherton — like-for-like work on what is already standing — and these are the questions we settle before anything is set. The wider picture for the neighbouring cities is in the fence rules and permits guide.