When a development project involves dividing land, combining parcels, or adjusting property boundaries, one of three instruments is used: a tentative map (and subsequent final map), a parcel map, or a lot line adjustment. The choice depends on how many lots are being created and the specific circumstances. Each has a different approval process, timeline, and set of conditions of approval. Using the wrong instrument delays the project and may require restarting the entitlement process.

Tentative Map (Subdivision Map)

A tentative map is required under the Subdivision Map Act (California Government Code Section 66426) when a property is being divided into five or more parcels (or four or more in some jurisdictions). It is the standard subdivision instrument for residential subdivisions, commercial lot splits, and any project that creates five or more new parcels.

The Two-Step Process

Subdivision approval is a two-step process:

1. Tentative Map — a conceptual plan showing the proposed lot layout, street alignment, utility routing, grading concept, and open space areas. The tentative map is reviewed by the planning department, public works, fire, water district, and other agencies. It is a discretionary approval, meaning the approving body (planning commission or city council) can deny it or impose conditions. Approval typically takes 3 to 12 months.
2. Final Map — a precise survey map prepared by a licensed land surveyor showing the exact lot dimensions, easements, dedications, and monuments. The final map must be consistent with the approved tentative map and must satisfy all conditions of approval. It is filed with the county recorder, at which point the new parcels officially exist. The final map is typically approved at the staff level (city engineer) rather than by the planning commission.

Conditions of Approval

Tentative maps come with conditions of approval that must be satisfied before the final map is recorded. Common conditions include:

• Install all public improvements (streets, storm drains, water mains, sewer, sidewalks) or post improvement bonds
• Dedicate right-of-way and easements to the city or public agencies
• Pay development impact fees (parks, schools, traffic, fire)
• Provide will-serve letters from all utility providers
• Record CC&Rs (covenants, conditions, and restrictions) if required
• Complete CEQA review or demonstrate CEQA exemption

Expiration

A tentative map approval expires if the final map is not recorded within the timeframe specified by the Subdivision Map Act (typically 24 months, with extensions available up to a maximum of 6 to 10 years depending on the legislative extensions in effect). Tracking expiration dates is critical — an expired tentative map requires a new application.

Parcel Map

A parcel map is used when a property is being divided into four or fewer parcels (or three or fewer in some jurisdictions). It is a simpler and faster process than a tentative map because it does not require the two-step tentative/final process. A single parcel map, prepared by a licensed surveyor and approved by the city engineer, is the entire instrument.

When It Is Used

• Splitting a large parcel into two to four lots for individual development
• Dividing a commercial property to sell a portion while retaining the remainder
• Creating a condominium subdivision (where the division is of airspace, not ground area)

Approval Process

Parcel maps may be approved ministerially (by staff) or discretionarily (by the planning commission or hearing officer), depending on the jurisdiction. Ministerial parcel maps can be approved in 4 to 8 weeks. Discretionary parcel maps may take 2 to 6 months.

Conditions of approval are similar to tentative maps but typically less extensive, because the project is smaller and generates fewer infrastructure demands.

Lot Line Adjustment

A lot line adjustment (LLA) moves the boundary between two or more existing adjacent parcels without creating any new parcels. The total number of parcels remains the same. An LLA is the simplest of the three instruments and has the fastest approval process.

When It Is Used

• A property owner wants to transfer a strip of land from one parcel to an adjacent parcel
• Two parcels need to be reconfigured (one gets larger, the other smaller) without creating new parcels
• A building straddles a property line and the line needs to be moved to put the building entirely on one parcel

What It Cannot Do

• Create a new parcel (that requires a parcel map or subdivision)
• Result in a parcel that does not meet minimum lot size, frontage, or setback requirements
• Create a landlocked parcel (every parcel must have legal access)

Approval Process

Lot line adjustments are typically ministerial approvals. The applicant submits a survey showing the existing and proposed lot lines, the planning department verifies that all parcels will comply with zoning, and the city engineer approves the map. Timeline: 2 to 8 weeks. Cost: $2,000 to $10,000 including survey and filing fees.

Which One Do You Need?

Action	Instrument
Divide a property into 5+ lots	Tentative Map + Final Map
Divide a property into 2-4 lots	Parcel Map
Adjust boundary between existing adjacent parcels	Lot Line Adjustment
Combine two adjacent parcels into one	Lot Merger (or Parcel Map in reverse)
Condominium conversion	Parcel Map or Tentative Map (depends on unit count)

Consult with the planning department before filing. The wrong instrument wastes filing fees and restarts the clock. A 15-minute pre-application meeting can prevent a 3-month delay.