Quick Reference Guide to the City of Palo Alto Building/Remodeling Requirements

Quick Reference Guide to the City of Palo Alto Building/Remodeling Requirements

Mia Simon & Ken DeLeonMarch 21, 2012

Many home buyers wish to purchase a lot in Palo Alto and build a home for themselves so that they can get exactly what they want in a house. Palo Alto is a moderately friendly city to builders, with the city taking steps to expedite the process and improve upon the “Palo Alto process,” the derogatory term for how long it used to take to get a home built in Palo Alto. While now more expeditious, building in Palo Alto still takes some time and thus, it is best to be familiar with an overview of the Palo Alto building procedures and work with a local architect who has built several homes in Palo Alto as well.

Below are some general guidelines:

 Size of home allowed on a lot

Floor Area Ratio (FAR): The total gross floor area on a single family lot can not exceed 45% of the first 5,000 square feet of lot area plus 30% of lot area over 5,000  square feet. The main house may not exceed 6,000 square feet, regardless of the size of the lot.

The following are the maximum floor areas for common Palo Alto lot sizes -

5,000 sq. foot lot = 2,250 sq. foot home

7,500 sq. foot lot = 3,000 sq. foot home

10,000 sq. foot lot = 3,750 sq. foot home

**Please note that the basement does not count towards the floor area ratio and that basements can increase square footage by more than 50% since they can be built under the entire footprint of the home. However, garages do count towards square footage which is why you see so many 1 car garages as builders seek to maximize the size of the home.

Garage Placement

Whether a garage can be placed in the front yard, (thus preserving the backyard space), is determined by contextual garage placement rules. Here are steps to making a rough determination:

  1. Consider the 10 lots closest to the subject lot, on the same side of the street as the subject lot.
  2. Exclude any flag lots, multi-family use homes of 3 units or more, and homes on the corner lot.
  3. Divide the remaining lots (including the subject lot) into two categories, a) lots with garage on the front half of the lot, and b) lots with garage on rear half of the lot or no garage.
  4. If more than half of the garages are in the front half of the yard, then the garage may be placed in the front or back. If more than half of the garages are in the rear half (or have no garage), then the garage must be on the rear half of the lot.


Setbacks apportion a lot into two parts, 1) buildable area and 2) required yards surrounding the buildable area.

The general setback requirements are:

Front- 20’

Rear- 20’

Interior Side- 6’

Street Side- 16’

Since corner lots have two front yards (with 20’ setback requirements), they are less attractive to developers because the greater setbacks lessen the size of the backyard.

** Please note that there can be other considerations such as easements, sidewalks, oddly shaped lots, flag and substandard lots, and contextual setbacks that affect the general rules.

Substandard lot requirements

For substandard lot sizes (where the width is less than 50’ or depth less than 83’), different rules may apply. One difference is that the maximum building height is single story. Also, for lots that are less than 50’ wide, the required street side yard is 10’ instead of 16’.

Parking spaces

Two spaces are required on the lot, per home. One of the spaces must be covered, but tandem parking is okay.

Second dwelling unit standards

Some lots are large enough to accommodate a second dwelling unit. In Palo Alto, the minimum lot size for a second dwelling unit is 8,100 sq. ft. The maximum size of an attached unit is 450 sq. ft. The maximum size of a detached unit is 900 sq. ft. The unit must have parking, must be located within the setbacks and does count towards the total floor area ratio for the lot.

A helpful guide that goes into more detail is “The Zoning Ordinance Technical Manual for Single Family Residential Zones.” This guide can be downloaded at: http://www.cityofpaloalto.org/civica/filebank/blobdload.asp?BlobID=8569

Fireplace Regulation

In 2000, the city of Palo Alto passed an ordinance prohibiting the construction of new wood-burning fireplaces. More information can be obtained at: http://www.cityofpaloalto.org/civica/filebank/blobdload.asp?BlobID=3690

Tree Regulation

In Palo Alto, there are three types of trees that are protected by law once they have grown to a specific size:

  1. The Coast Live Oak is protected when the tree measures more than 11.5 inches in diameter.
  2. The Valley Oak is protected when it measures more than 11.5 inches in diameter.
  3. The Coast Redwood is protected when it measures more than 18 inches in diameter.

For more details regarding tree regulation, please visit: http://www.cityofpaloalto.org/civica/filebank/blobdload.asp?BlobID=2591

About the author:

Mia began her career as an associate at a large, international law firm, and then made the leap in 2009 from practicing attorney to real estate broker. As buyer’s consultant to Ken Deleon, Mia enjoys an innovative and unique arrangement as a salaried employee (paid on customer satisfaction and not commission).  Her training as an attorney and subsequent work within real estate has fueled an interest in the building code and permitting process within Palo Alto.

This article is intended to provide general guidance pertaining to certain elements of the Palo Alto code as of 2011. It is not a substitute for a thorough on-site review and evaluation by a qualified attorney or other professional. There are many other rules and restrictions that pertain to certain properties or areas. Readers should not rely upon this article as a substitute for professional advice.