An extra apartment in a San Francisco listing may be described as an in law unit, garden unit, accessory dwelling unit, or bonus living space. Those descriptions can be useful for marketing, but they do not answer the same question as a city approval record. To investigate whether the space is authorized as a separate dwelling, identify the exact space and trace the documents that address its use.
San Francisco Planning distinguishes accessory dwelling unit programs from other ways an existing unauthorized unit may be legalized. Its guidance also explains that living space can be added without creating a separate dwelling. That makes the actual approved use more important than the presence of a kitchen, a separate entrance, or a familiar listing term.
Describe the space you are investigating
Start with the property's full address and the location of the extra space within it. Record the floor, entrance, unit label, and relationship to the main dwelling as described in the listing or owner documents. If the same space has different names in different records, preserve those names rather than deciding prematurely that they are interchangeable.
Ask whether the claim concerns an existing authorized unit, a proposed new unit, or an existing space undergoing legalization. These are different situations with different document trails. A statement that the property could have an ADU does not establish that the current space is already approved for separate occupancy.
Avoid inferring authorization from utility arrangements, rental history, or tax information alone. Such records may help identify the space or its history, but they do not necessarily answer the building and planning approval question. Keep them as supporting context and ask which city document establishes the specific residential use being claimed.
Separate program eligibility from completed approval
Planning's ADU page describes local and state program routes and notes that some unauthorized units can be legalized through those routes or other available processes. A program description is general information. It does not determine that an individual property qualifies or that a project has completed the required review.
For an existing unauthorized unit, Planning's legalization guidance directs readers to the Department of Building Inspection for eligibility questions. Because the available route may depend on property details and current rules, ask the city which process applies to the actual case. Do not select a route merely because its general description seems easier or faster.
Keep three statements separate in your notes: the owner believes the unit is eligible, an application has been submitted, and the necessary approvals have been completed. Each requires different evidence. Collapsing them into the single phrase legalization underway can leave a renter or buyer unclear about what remains before the claimed use is established.
Request the documents behind the claim
Ask the owner or representative for the permit or application numbers related specifically to creating or legalizing the unit. Request the description of work and the relevant approved plans where available. A folder of unrelated repairs can demonstrate activity at the property without showing that the extra space was approved as a separate dwelling.
Match each identifier to the correct address and scope. A permit for a bathroom repair, electrical work, or a general renovation may not authorize a change in dwelling count. Read the description before deciding that the permit answers your question. If the wording is too broad to interpret confidently, ask DBI or Planning which associated record provides the needed detail.
Also request the document that supports the claimed completion status. Do not assume that permit issuance means all work and inspections are finished. The right question is what official evidence establishes the final approved condition for this particular project. The city can clarify which completion or occupancy record is relevant rather than relying on a universal document name chosen from another jurisdiction.
Compare the approved use with the offered use
Review how the plans describe the space. Is it identified as part of an existing dwelling, storage, another use, or a separate dwelling? Compare that description with what is being offered. A difference does not automatically resolve the legal question, but it creates a concrete issue to raise with the city and property representative.
Planning's current ground floor development affidavit warns that using rooms differently from approved plans can trigger additional requirements and costs. This makes plan labels consequential. A room that looks residential in photographs may still require clarification if the approved documents describe a different use or relationship to the rest of the building.
Check whether later revisions changed the earlier plan. Retain revision dates and sheet references. An old approved drawing can be superseded, while a proposed revision may never have been approved. Ask which version represents the completed project. Do not combine favorable details from different versions into an imagined approval that appears nowhere in the record.
Use a unit authorization worksheet
Create a worksheet with five columns: claim, supporting document, exact location in the document, current uncertainty, and question for the responsible office. For example, the claim might be that a rear space is a separate dwelling. The supporting document could be a permit description, while the uncertainty concerns whether the final plans identify that same rear space.
Include a separate identity line for the property and unit. This is especially helpful when an application refers to the whole building but a listing concerns only one portion. The worksheet should make clear how you connected the record to the space under consideration. If that connection is not established, say so explicitly.
Avoid turning the worksheet into a compliance certificate. It is a research aid that helps organize questions and preserve the answers. A complete looking spreadsheet does not replace the city's determination, a professional review, or the current physical condition of the property. Its value lies in traceability rather than an appearance of authority.
A fictional document trail
Imagine a fictional listing advertising a newly created garden apartment. The seller supplies a permit for ground floor alterations and says the space is ready to rent. The buyer reads the permit description but cannot tell whether it creates a separate dwelling or expands the existing home. The buyer requests the relevant approved plans and final status information.
The plans supplied show rooms connected to the main dwelling, while a separate application proposes an ADU. The buyer records both documents without assuming that the second application changed the first approval. The next question to the city is whether the ADU application has produced the approvals and completion records necessary for the offered configuration.
Suppose the city identifies a later approved revision and explains the remaining project steps. The buyer updates the worksheet and asks the transaction professionals how the unresolved work affects the proposed purchase. This example does not determine a real unit's legality. It shows why a permit number and a listing description must be connected through the actual scope and status documents.
Investigate discrepancies without inventing conclusions
If the unit count differs across records, record each source and date. A planning map, assessment record, advertisement, and permit file may serve different purposes or reflect different points in time. Ask the responsible office which record answers the current authorization question. Do not simply choose the highest count or the most recently updated website.
If no matching record appears in an initial search, describe the result narrowly. The absence of a result under one address or keyword is not a definitive determination that no approval exists. Ask about alternate identifiers, archived records, or the appropriate request process. Equally, the possibility of an older record is not evidence that the unit must be authorized.
Where documents are incomplete, request a written explanation of what is known and what remains missing. Avoid accepting an unsupported statement that older buildings are exempt from all relevant approval questions. The age of the space may matter to the applicable process, but it does not eliminate the need to establish which rules and records apply.
Ask a focused city question
A useful inquiry names the address, describes the exact extra space, and identifies the permit or application being reviewed. Attach only the relevant pages initially and explain the apparent mismatch. Ask which approved document establishes the use and what record confirms the project status. This gives staff a concrete question rather than asking them to evaluate an entire sales presentation.
Retain the reply with the document version it addresses. If the owner later supplies a different plan or completion record, ask whether that changes the earlier answer. An explanation about one application should not be applied automatically to another application simply because both concern the same building.
Keep tenancy and transaction decisions separate
A records question can have implications for a rental or purchase, but it does not by itself determine every party's rights or obligations. A current occupant should not assume that an uncertain unit record automatically ends a tenancy or requires an immediate move. A buyer should not assume that an unresolved approval will be inexpensive to complete. Those are separate questions requiring advice appropriate to the circumstances.
When a decision depends on authorization, share the actual documents and the city's response with the qualified adviser handling that decision. A summary such as probably legal loses the details needed to assess the issue. Provide the permit numbers, plan versions, remaining steps, and any deadline connected with the transaction.
The strongest research outcome is a clear statement of the exact space reviewed, the approval route identified, the documents supporting its use, and any unresolved completion question. San Francisco's ADU and legalization resources can help locate the right process. They become most useful when paired with property specific records rather than treated as a blanket assurance about every extra rental unit.