The Visibility Test

The visibility test sits inside the South Pasadena ADU framework for historic properties, not in the general Article IVH Certificate of Appropriateness framework. Two layers of authority apply, and getting the source attribution right matters:

• The underlying authority is the zoning code at SPMC 36.350.200(J), which establishes the Design Standards framework for ADUs on Inventory properties. This is the ordinance.
• The procedural articulation of the test — the geometric definition, the corner-property treatment, the alley exclusion, the landscaping non-factor — is in the City’s Design Guidelines for ADU Development on Historic Properties, prepared by Architectural Resources Group (ARG), dated November 2, 2021. The Guidelines are supporting guidance — explanatory and illustrative material that develops what the underlying Design Standards require.

The current zoning-code text at SPMC 36.350.200(J) is among the package-lock items pending direct verification before publication. State ADU law has continued to evolve through SB 897 and subsequent amendments, and the zoning-code text may have been updated since the ARG 2021 Guidelines were published. This entry describes the visibility test as articulated in the ARG 2021 supporting guidance. Owners scoping an ADU on a historic property should confirm the current zoning-code text and any post-2021 amendments before treating the test mechanics here as definitive.

The visibility test applies only to ADU projects on properties listed on the South Pasadena Inventory of Cultural Resources. It is not a general historic-resource rule under Article IVH. A non-ADU alteration on an Inventory property — for example, a window replacement, a roof material change, a porch reconstruction, or a second-story addition — is reviewed under the Certificate of Appropriateness framework at SPMC 2.65, where the visibility test does not apply. The relevant findings architecture for non-ADU alterations is the three-mandatory-plus-three-of-twelve structure at SPMC 2.65(e)(10), not the ministerial-vs-discretionary outcome that flows from the visibility test in the ADU framework.

Per the ARG 2021 Design Guidelines (supporting guidance), an ADU is considered “visible from the public right-of-way” if it is visible from the street immediately in front of and within 10 feet on either side of any street-adjacent property line. The geometry establishes a defined viewing zone from which visibility is assessed. ADUs that fall within the viewing zone, as the test articulates it, are typically subject to the Design Standards for visible ADUs. ADUs that fall outside it are typically exempt from the visibility-driven design requirements.

For corner properties, both adjacent streets are considered for purposes of the visibility test. An ADU may fall inside the viewing zone of either street individually, and the cumulative result determines whether the test treats the ADU as visible.

Alleys do not count as public right-of-way for purposes of the visibility test as articulated in the Guidelines. An ADU that is visible only from an alley typically falls outside the visibility threshold. This is a meaningful practical detail: properties with rear-alley access often have ADU siting options that would be more constrained on a non-alley parcel of similar dimensions.

Vegetation, gates, fencing, and other landscaping are not factored into the visibility test. They cannot be relied on to bring an otherwise visible structure under the threshold. The reason for the exclusion is straightforward: vegetation can be removed, fencing can be replaced, and landscape conditions change. The test evaluates the structural visibility of the ADU itself, independent of softscape conditions that are not durable.

An ADU project that meets the visibility test (i.e., is not visible from the public right-of-way as the test defines it) and that complies with the other applicable ADU Design Standards typically proceeds through ministerial (staff-level) approval. There is no discretionary Cultural Heritage Commission hearing, and no Certificate of Appropriateness is required — the SPMC 2.65(d)(6) categorical ADU exemption from the CoA framework continues to apply. “Typically” is the operative word; the actual outcome depends on staff review of the application against the standards as a whole, not the visibility test alone.

An ADU project that fails the visibility test, or that meets the visibility test but does not comply with one or more of the other applicable Design Standards, may require Cultural Heritage Commission review. That review proceeds under the parallel zoning-code review track established at SPMC 36.350.200(J) — not under the Article IVH Certificate of Appropriateness framework. The Commission then reviews the project against the Design Guidelines and the Secretary of the Interior’s Standards through the zoning-code track.

Bears repeating: the visibility test is a feature of the ADU framework on historic properties. It is not a general rule applied to non-ADU work on Inventory properties, and it is not articulated in Article IVH itself. An owner scoping a kitchen remodel, a porch reconstruction, or a second-story addition on an Inventory property should not assume the visibility test applies. Those projects are evaluated under the SPMC 2.65 Certificate of Appropriateness framework, where the relevant analytical question is character-defining-feature impact and the relevant findings structure is the three-mandatory-plus-three-of-twelve architecture.

Source: South Pasadena Municipal Code Chapter 36, § 36.350.200(J) — Design Standards for ADUs on Historic Properties (current text package-locked pending direct verification). City of South Pasadena, Design Guidelines for ADU Development on Historic Properties, prepared by Architectural Resources Group, November 2, 2021, pp. 13–14 (supporting guidance — the source of the test’s procedural articulation). SPMC § 2.65(d)(6) (categorical CoA exemption for ADUs on historic properties).