4.2 Applying the Subdivision Map Act: Triggers, Waivers, and Exceptions

Independent OpenExamPrep teaching for activity I.10: apply the Subdivision Map Act and other related laws. January 2025 test-plan knowledge O through R, including P (map waivers, SMA 66428) and Q (exceptions, SMA 66412), sits here at business level: when tentative, parcel, and final maps are required; who may waive a parcel map; which transactions are outside the Act; and how state and local submittal, review, and filing intercept a false Record-of-Survey split. Domain V later teaches map elements. This section teaches the trigger.

What subdivision means before you pick a map

The Subdivision Map Act (SMA) is Division 2 of Title 7 of the Government Code, commencing with section 66410. Government Code 66411 vests regulation and control of the design and improvement of subdivisions in the legislative bodies of local agencies, and requires each local agency, by ordinance, to regulate initial design and improvement of common-interest developments and of subdivisions for which the division requires a tentative and final or parcel map.

Government Code 66424 defines subdivision: the division, by any subdivider, of any unit or units of improved or unimproved land, or any portion thereof, shown on the latest equalized county assessment roll as a unit or as contiguous units, for the purpose of sale, lease, or financing, whether immediate or future. Property is contiguous even if separated by roads, streets, utility easement, or railroad rights-of-way. The definition includes a condominium project (Civil Code 4125 or 6542), a community apartment project (Civil Code 4105), and conversion of five or more existing dwelling units to a stock cooperative (Civil Code 4190 or 6566).

Two business consequences follow. First, a client who only wants to lease a pad or finance later can still be subdividing. Second, two assessor parcels separated by a county road can still be contiguous units for 66424. Do not tell a client that a road between the tax lots automatically prevents a subdivision.

Government Code 66411 also lets local agencies regulate other subdivisions by ordinance, but those local rules may not be more restrictive than the regulations for subdivisions that require a tentative and final or parcel map under the Act, with a stated railroad short-term-lease exception.

The ordinary map split: five-or-more versus four-or-fewer

Government Code 66426 requires a tentative and final map for all subdivisions creating five or more parcels, five or more condominiums, a community apartment project containing five or more parcels, or conversion of a dwelling to a stock cooperative containing five or more dwelling units, except where any of the following occurs:

(a) The land before division contains less than five acres, each parcel created abuts a maintained public street or highway, and no dedications or improvements are required by the legislative body.

(b) Each parcel created has a gross area of 20 acres or more and has approved access to a maintained public street or highway.

(c) The land has approved access to a public street or highway, comprises part of a tract zoned for industrial or commercial development, and has governing-body approval as to street alignments and widths (the designed street geometry the local body approved—not a claim about this study guide or the Board).

(d) Each parcel created has a gross area of not less than 40 acres or is not less than a quarter of a quarter section.

(e) The land is solely for an environmental subdivision under 66418.2.

66426(f) then states that a parcel map shall be required for those subdivisions described in (a) through (e). A 66426 exception does not mean no map. It means no tentative-and-final pair; you still prepare a parcel map unless a 66428 waiver applies.

For divisions that are not in the 66426 five-or-more class, the ordinary statewide tool is a parcel map. Government Code 66428(a) says local ordinances may require a tentative map where a parcel map is required, and that a parcel map shall be required for subdivisions as to which a final or parcel map is not otherwise required, unless the parcel map is waived by local ordinance as provided in 66428. A parcel map is not required for (1) certain short-term railroad operating right-of-way leases (terminable on not more than 30 days' written notice), or (2) land conveyed to or from a governmental agency, public entity, or public utility (including a utility subsidiary for rights-of-way), unless a showing is made on substantial evidence that public policy necessitates a parcel map. For that conveyance clause, land includes a fee, leasehold, easement, or license.

Government Code 66428(b) is the waiver engine. A local agency shall, by ordinance, provide a procedure for waiving the parcel-map requirement imposed by the division, including parcel-map requirements imposed by 66426. The procedure may include waiving tentative and final maps for construction of a condominium project on a single parcel. The ordinance shall require a finding by the legislative body or advisory agency that the proposed division complies with SMA and local-ordinance requirements as to area, improvement and design, floodwater drainage control, appropriate improved public roads, sanitary disposal facilities, water supply availability, environmental protection, and other SMA or local requirements. Where a parcel map is waived, a tentative map may still be required by local ordinance. 66428(c) lets the subdivider submit a tentative map, or a vesting tentative map under Chapter 4.5 (commencing with 66498.1), if local ordinance does not already require a tentative map.

You do not waive a parcel map by writing a letter on your letterhead. The local ordinance and the required findings waive it. A certificate of compliance under the SMA's later enforcement provisions (including Government Code 66499.35) is a related agency document used to document that real property complies with the Act; it is not a private substitute for 66428 findings. Confirm the local procedure before you quote a client a map-waiver fee.

Government Code 66448, at business level only: where a parcel map is required, it shall be based on a field survey in conformity with the Land Surveyors Act when local ordinance requires that, or, if not, either on such a field survey or compiled from recorded or filed data when sufficient recorded or filed monumentation exists to retrace the exterior and establish interior lines. Whether your county requires a field survey is a local ordinance question. Do not assume every two-lot split is compile-from-record.

Exceptions under 66412, especially lot line adjustments

Government Code 66412 states that the SMA shall be inapplicable to listed transactions. The current LegInfo text of 66412 runs (a) through (o) after SB 347, Statutes 2024, Chapter 591, effective January 1, 2025, which added hydrogen-fueling and electric-vehicle charging station leases and easements as (o). Exam-relevant business items include:

• (a) Financing or leasing of apartments, offices, stores, or similar space within apartment, industrial, or commercial buildings, mobilehome parks, or trailer parks.
• (b) Mineral, oil, or gas leases.
• (c) Land dedicated for cemetery purposes under the Health and Safety Code.
• (d) A lot line adjustment between four or fewer existing adjoining parcels, where land taken from one parcel is added to an adjoining parcel, and a greater number of parcels than originally existed is not thereby created, if approved by the local agency or advisory agency.
• (k) Leases of agricultural land for agricultural purposes (cultivation of food or fiber, or grazing or pasturing of livestock).

66412(d) is the land-surveyor workhorse. Local review is limited to whether resulting parcels will conform to the local general plan, any applicable specific plan, any applicable coastal plan, and zoning and building ordinances. The agency shall not impose conditions or exactions except to so conform, to require prepayment of real property taxes before approval, or to facilitate relocation of existing utilities, infrastructure, or easements. No tentative map, parcel map, or final map shall be required as a condition of approving the lot line adjustment. The adjustment shall be reflected in a deed, which shall be recorded. No Record of Survey shall be required for a lot line adjustment unless required by BPC 8762. Local agencies approve or disapprove under the Permit Streamlining Act.

That last Record of Survey sentence is the trap. A lot line adjustment is outside the SMA map requirement, but it is not outside the Professional Land Surveyors' Act. If the field survey discloses a 8762(b) condition, file the Record of Survey. If it is a clean retracement that meets 8765(d), a corner record may be the filing. The recorded deed carries the new lines; the Record of Survey does not create a fourth lot.

Worked example: six lots

A rancher wants six home sites, each about two acres, from one 14-acre assessment parcel that does not meet 66426(a)–(e). 66426 requires a tentative map and a final map. You may also have local design, improvement, and environmental processing. Quoting only a Record of Survey is an unlawful offer: BPC 8762.5 will stop an ROS that shows the division. Selling or financing lots without complying with the SMA is an SMA enforcement problem, not a surveying discount.

Worked example: two lots

The same rancher wants two parcels. That is ordinarily a parcel map under 66428(a), and local ordinance may also require a tentative parcel map. If the local waiver ordinance applies and the legislative body or advisory agency makes the 66428(b) findings, the parcel map can be waived. You still prepare whatever local tentative, exhibit, legal descriptions, and certificate-of-compliance process the agency uses. You still monument and file under the PLS Act if 8762 or 8773 is triggered.

Worked example: three-lot line adjustment

Three existing adjoining lots; the owner wants to move a side line so a garage setback works. No new parcel is created. 66412(d) can apply if the agency approves. You prepare the deeds and typically a plat exhibit. You do not condition the approval on a parcel map. You do run the 8762 checklist on the field survey.

Submittal, review, and filing are local plus the SMA: tentative maps go to the advisory agency or legislative body; final and parcel maps go to the city engineer or county surveyor for examination and to the recorder for filing. BPC 8762.5 is how an attempted Record-of-Survey split is intercepted. Quote local filing windows from the ordinance, not from folklore. The statewide clocks you can name without a local book are the PLS Act clocks in section 4.1 (90 days, 20 working days), not a universal SMA tentative-map day count that the Map Act does not publish as a single number for every city.