Merger vs. Reversion to Acreage

[Jedwards]

Hi all,

I’m trying to better understand the distinction between a Merger and a Reversion to Acreage under the Subdivision Map Act.

Per GC 66499.20.3 - A city or county may, by ordinance, authorize the merger of contiguous parcels under common ownership without reverting to acreage. The ordinance shall require the recordation of an instrument evidencing the merger.

This section of the SMA makes me think that as long as the agency allows for a merger it would always be the best option with the fewest steps. Am I missing anything? Are there any situations where a Reversion to Acreage is needed?

Thanks,

Jacob Edwards

[steffan]

One type of merger is the option for owner initiated merger. However, many (maybe most?) local agencies have not passed the ordinance required for this option. Another type of merger is the agency initiated process, where the agency desires to force owners to merge parcels. Reversion to acreage can be either owner or agency initiated but appears to be applicable only to entire subdivisions, not portions.
Lot line adjustments have been successfully used to merge parcels in some jurisdictions. However each agency has a different thought process and procedure on how this all works.
On a side note, I know of one city that requires owners to pay for a merger process before allowing a lot line adjustment of the subject parcels, which makes absolutely no sense at all.

[John Williams, PLS]

I was involved in a reversion to acreage map a while back. If I recall correctly, the situation was basically to reverse a tract map back to original acreage including previously dedicated roads and the like. The large parcel was then redeveloped in a new configuration.
I believe 66499.20.3 may be a County initiated merger based on contiguous common ownership of sub-standard lots to do not meet code compliance i.e. minimum square footage etc.
Some Counties have a simple merger document, others require a Lot Line Adjustment.
J-Dub

[DWoolley]

These are two distinct statutory tools serving different purposes.

A merger is straightforward. It is the consolidation of contiguous parcels, typically as an administrative remedy to address parcels that were improperly created or that no longer meet current standards.

A reversion to acreage, by contrast, is the formal undoing of a subdivision. For example, a developer records a parcel map creating four lots with dedications to the City or County. A subsequent owner acquires all four lots for a single use, such as agricultural or equestrian purposes. A reversion to acreage eliminates the lot lines and returns the property to undivided acreage status, subject to statutory conditions. The map eliminates the dedications to the public agency authorizing the map.

Importantly, a reversion does not automatically extinguish all rights created by the original subdivision. In 1993, I authored the clarifying language adopted in AB 557, which amended Government Code section 66499.20½ (the so-called “half rule”). That amendment made clear that a reversion to acreage does not extinguish easements or dedications granted to other public or private entities (not the city or county). The change was modest in form, but critical in effect, as it resolved persistent ambiguity regarding the survival of third-party rights following a reversion.

In the more than 35 years of map checking in multiple jurisdictions, I have only reviewed a handful of reversions to acreage.

DWoolley

[DWoolley]

While on the subject of improper subdivision practices, there are jurisdictions that permit mergers of more than four parcels, or worse, tacitly allow and even encourage the serial use of lot line adjustments to achieve the same result.

A common example involves nine existing lots. Four lots are merged into one. Another four lots are merged into a second lot. The remaining three lots are then merged into a third lot. Through a sequence of administrative actions, the practical effect is the merger of more than four parcels without ever complying with the statutory requirements for a subdivision or reversion.

This practice is a transparent end run around the Subdivision Map Act. Fragmenting a prohibited outcome into multiple steps does not legitimize it. The Act regulates results, not clever sequencing.

Proponents often cite Sierra Club v. County of Sonoma in support of this approach. That reliance is misplaced. The case does not stand for the proposition that agencies may evade statutory parcel limits through serial administrative actions. Using it to justify multi-step parcel consolidation is a misreading of both the holding and the intent of the Subdivision Map Act.

Unfortunately for the public, administrative tolerance of these practices ensures there is no shortage of land surveyors willing to operate in the shade and under the cover of darkness. I recently chose professional withdrawal as the map checker of record rather than participate in that conduct. I was advised that my ethics were appreciated, but that the jurisdiction must remain “developer friendly,” and that another surveyor would be engaged to sign the documents.

DWoolley

[Elias French]

Great question and answer.

For voluntary mergers authorized by ordinance, from memory I did not think them limited to four or fewer lots. As would be a lot line adjustment.

Thanks in advance for any input, especially from locales with such an ordinance.
Elias French

[Jedwards]

Thanks everyone for the input. This is extremely helpful since there’s limited guidance on reversions, likely due to how uncommon they are.

Based on the discussion and examples shared, my understanding is that a Reversion to Acreage is intended to undo an entire subdivision map, including associated public dedications and conditions. Completing a Reversion to Acreage of said subdivision map would allow for further subdivision of the parcel.

Since the applicant here is proposing to merge only two lots within an eight-lot subdivision, I’m leaning toward a merger process as the more appropriate path. I appreciate the feedback as I work through this case study.

Thanks,

Jacob Edwards

[DWoolley]

In my experience, reversions to acreage tend to occur in the years following financial recessions. Subdivision maps are often filed by developers who subsequently fail - they may believe that entitled lots will carry greater value for a successor. When ownership changes, the next developer has a different development concept, making the existing subdivision obsolete and prompting a reversion.

While discussing improper application of provisions under the Subdivision Map Act, I have also encountered jurisdictions that incorrectly rely on amended maps to relocate title boundary lines. In one instance, a land surveyor prepared and recorded a parcel map with an exterior boundary error on the order of twenty feet. When the error was later identified, the surveyor was uncertain how to lawfully remedy the defect. Rather than requiring an appropriate statutory or judicial process, the County advised use of an amended map. The surveyor complied, resulting in a post-recordation relocation of the boundary.

In another instance, another county similarly approved an amended map to shift a boundary line approximately ten feet in order to accommodate the constructed location of a building. There are only remnants left of the profession.

An amended map does not provide authority to revisit or relocate title boundary lines. It functions much like a certificate of correction (that is why the law states "a certification of correction or amended map..."). Once a subdivision or parcel map is filed, the boundary framework reflected on that map is fixed for purposes of title. If the original boundary establishment was incorrect, that error cannot be cured administratively through an amended map, regardless of how compelling the surveying evidence may be. Changing title lines post-recordation requires a new statutory process or judicial action, not a corrective filing.

This matters because the same logic applies to mergers and serial lot line adjustments. Agencies sometimes treat administrative tools as interchangeable or harmless when used incrementally. They are not. The Subdivision Map Act regulates outcomes, not sequencing. Breaking a prohibited result into smaller administrative steps does not legitimize it, and using corrective mechanisms to achieve substantive boundary changes undermines the integrity of the public record.

Local ordinances vary, but the legal constraints do not disappear simply because a process is labeled “administrative.”

DWoolley

[DWoolley]

For the uninitiated, Government Code § 66469:

After a final map or parcel map is filed in the office of the county recorder, it may be amended by a certificate of correction or an amending map for any of the following purposes:

(a) To correct an error in any course or distance shown thereon.
(b) To show any course or distance that was omitted therefrom.
(c) To correct an error in the description of the real property shown on the map.
(d) To indicate monuments set after the death, disability, retirement from practice, or replacement of the engineer or surveyor charged with responsibilities for setting monuments.
(e) To show the proper location or character of any monument which has been changed in location or character, originally was shown at the wrong location, or incorrectly as to its character.
(f) To correct any additional information filed or recorded pursuant to Section 66434.2, if the correction does not impose any additional burden on the present fee owners of the real property and does not alter any right, title, or interest in the real property reflected on the recorded map.
(g) To correct any other type of map error or omission as approved by the county surveyor or city engineer that does not affect any property right, including, but not limited to, lot numbers, acreage, street names, and identification of adjacent record maps.

As used in this section, “error” does not include changes in courses or distances from which an error is not ascertainable from the data shown on the final or parcel map.

Does anyone see it differently?

DWoolley

[Jim Frame]

I don't do many subdivisions -- I don't enjoy the tedious process with its endless back-and-forth that stretches over years. (I'm *almost* done with a Parcel Map that I started work on almost 2 years ago, and will be delighted when I can finally close out that job!) Not knocking those who do them, I only say this to underscore the fact that I'm not an expert on the SMA, which leads me to my ingenuous question: what is the public policy behind requiring a map to accomplish a reversion to acreage, versus a simpler ministerial procedure? Aside from the matter of erasing any bona fide rights that may have been acquired when the subdivision was filed, is there some other reason to impose the more elaborate and costly procedure?