The Map Act excludes certain activities that might otherwise be considered a subdivision of property. Some examples of such exclusions can be found in Government Code § § 66411, 66412.1-.7, 66424, 66428, and 66451.7, and include such things as mineral, oil and gas leases; land dedicated for cemetary purposes; lot line adjustments; and financing or leasing of offices.

When there is an issue as to whether a lot is "legal," the resolution often involves the issuance of a "certificate of compliance" or a "conditional certificate of compliance." The issuance of certificates of compliance are ministerial acts. If the lot in question complies with the provisions of the Map Act, or conditions can be imposed on the lot so as to bring the property in compliance with such provisions and ordinances, then the city/county must issue the certificate. Gov. Code § 66499.35.

The Map Act mandates an initial two-year life to tentative maps, and by ordinance, the city/county can extend that initial life for an additional 12 months. Gov. Code § 66452.6(a)(1). Fortunately, the Map Act provides many tentative map extension opportunities. Thus, unless a final map is filed with the city/county within the initial life of the tentative map or the life of the tentative map is extended, the tentative map will expire. Gov. Code § 66452.6(d). If the tentative map expires, the process starts all over again: a new tentative map application will have to be prepared, processed and approved. Gov. Code § 66452.6(d).

The Map Act allows local governments flexibility in processing map applications. A city/county can determine by local ordinance who "hears and decides" maps (e.g., planning commission, departmental officer, committee of officials, city council/board of supervisors, etc.). Gov. Code § 66458.

The Map Act requires timely action by the local agency. However, there can be no automatic approval of a tentative map, until due process is satisfied and a determination that the tentative map is consistent with the general plan is made.

Cities/counties may impose conditions on the map approval such as parkland dedications, school fees and dedications, reservations for public purposes, street dedications, fees and/or dedications for bicycle paths, bridges, groundwater recharge, etc. Gov. Code § § 66475-66489. In theory, the basis for the imposition of conditions is quite simple - the developer, in return for the land provides to the city/county the amount of land (or money) needed to provide certain services necessitated by the influx of new residents or employees in the community that such development attracts. Associated Homebuilders Etc., Inc. v. City of Walnut Creek, 4 Cal.3d 633 (1971). In attaching such conditions, the city/county relies on its police powers and those statutes granting such authority. Therefore the issue becomes to what extent may a city/county condition the map (with impact fees and land dedications) under controlling state and federal law.

The Subdivision Map Act provides a means to secure "vested rights" against later changes in local regulations. For example, "Vesting Tentative Maps" confer a vested right to proceed with the development in accordance with the local laws in place at the time the map application is completed. Gov. Code § § 66498.1, 66474.2. Once such a right is in place, the city/county may not condition or deny a subsequent permit, approval, extension, or entitlement unless it determines: (1) that failure to do so would place the residents of the subdivision or the immediate community, or both, in a condition dangerous to their health or safety, or both; and/or (2) the condition or denial is required, in order to comply with state or federal law. Gov. Code § 66498.1. The "life" of such vested rights are likewise controlled by the Map Act.

The Map Act sets forth the detailed procedures relating to the form, contents, and processing of tentative, final and parcel maps. Gov. Code § § 66433-66443 (Final Maps) and 66444-66450 (Parcel Maps). Pursuant to the Map Act, the controlling discretionary action to be taken by a city/county relating to subdivision map action is at the tentative map or parcel map approval stage. The city/county is required to provide notice and a public hearing before approving or conditionally approving a map. Gov. Code § 66473.5. A city/county, however, shall not approve a final or parcel map unless it is consistent with the general or specific plan, which must be substantiated through its findings. Failure to make the findings described in the Map Act is grounds for denial of a map. Gov. Code § 66474.

Any action or proceeding challenging the decision to approve or deny a map must first be appealed to the highest city/county level allowed and then must be filed with the court within 90 days after the date of such final local decision. Gov. Code § 66499.37. When challenging a city's/county's decision to approve a proposed project, all issues, legal and factual, must first be presented to the city/county (under the doctrine of exhaustion of administrative remedies).

"Antiquated subdivisions" or "old maps" generally refer to maps recorded prior to 1893, the enactment date of the first statewide Map Act. The modern Map Act provides exemption language for these subdivisions under Government Code § § 66499.30(d), 66451.10, and 66412.6. These grandfather provisions generally recognize an old map when it was recorded in compliance with the laws governing the map in effect at the time the map was recorded. If there were specific laws regulating the content or recording of maps, and the map was in compliance with them, or there were no laws regulating mapping, but the map was legally recorded, then it falls within the statutory exception. Likewise, separate "validation" statutes even protect and grandfather improperly recorded maps.