Lot splits under SB 9 in San Marcos: the local rules

Each rule below links to the section of the San Marcos Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What San Marcos's code says

San Marcos code What San Marcos's code adds
How the lot may be divided	2 parcels of about equal area; neither may be smaller than 40% of the original lot. Applies: Applies to urban lot splits in a single-family residential zone. § 19.44.050 · code text Both newly create parcels shall be of approximately equal lot area, which for purposes of this paragraph shall mean that one parcel shall not be smaller than 40 percent of the lot area of the original parcel proposed for subdivision.
Minimum new lot size	Each new parcel must be at least 1,200 square feet. § 19.44.050 · code text Both newly created parcels shall be no smaller than 1,200 square feet.
Standards	Units may be at most 16 feet tall and 1 story. Applies: Applies to units built on an urban lot split, measured from the lower of existing or finished grade. § 19.44.050 · code text Units constructed on an urban lot split subdivision approved pursuant to this chapter shall not exceed sixteen feet (16') in height and one story, measured from preexisting grade or finished grade, whichever is lower, to the highest point of the roof. Each unit must have vehicle access to and from the public right-of-way. Applies: Applies to each unit on a parcel created by an urban lot split. § 19.44.050 · code text Each unit located on a parcel created pursuant to this chapter shall have vehicular ingress and egress to the public right-of-way. Only residential uses are allowed. Applies: Applies to parcels created by an urban lot split. § 19.44.050 · code text The uses allowed on a parcel created pursuant to this chapter shall be limited to residential uses. No more than 2 lots, and no more than 4 units in total across the 2 lots. Applies: Applies to an urban lot split map. § 19.44.110 · code text The subdivision proposed creation of more than two lots or more than four units total among the two lots.
Owner occupancy	A recorded affidavit to live in one unit as the main home for at least 3 years from approval. Applies: Applies to urban lot split applicants, except community land trusts and qualified nonprofit corporations. § 19.44.030 · code text An applicant for an urban lot split subdivision shall sign and submit with the application an affidavit stating that the applicant intends to occupy one of the housing units as their principal residence for a minimum of three (3) years from the date of the approval of the urban lot split. No owner-occupancy affidavit is required. Applies: Applies when the applicant is a community land trust or a qualified nonprofit corporation. § 19.44.030 · code text An affidavit shall not be required of an applicant that is either a "community land trust" or a "qualified nonprofit corporation" as defined in the Revenue and Taxation Code.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

Can I split my lot under SB 9 in San Marcos?

San Marcos's code: Each new parcel must be at least 1,200 square feet. (§ 19.44.050); A recorded affidavit to live in one unit as the main home for at least 3 years from approval. (Applies to urban lot split applicants, except community land trusts and qualified nonprofit corporations.) (§ 19.44.030).

Lot splits under SB 9 in San Marcos

What San Marcos's code says

Who this affects

Frequently asked questions

Ask about a specific San Marcos property

More on building on your lot in San Marcos