This class of district is intended to provide a mix of multi-family residential uses and space for local retail, consumer service businesses, and professional services necessary to serve primarily the town and its spheres of influence. Any parcel in an M-U district may be occupied by a principal use listed in Section 18.23.020 or, when authorized by the planning commission, by a conditional use listed in Section 18.23.030 together with uses accessory to such principal use or conditional use as specified in Section 18.23.040. Use of any parcel is subject to:

A.

Development standards set forth in Section 18.23.050;

B.

Design standards set forth in Section 18.23.060;

C.

The required conditions set forth in Section 18.23.070;

D.

The provisions governing accessory uses set forth in Chapter 18.42;

E.

The provisions regulating fences set forth in Chapter 18.43;

F.

The provisions regulating nonconforming uses set forth in Chapter 18.46;

G.

Yards, building bulk, and site design requirements set forth in Chapters 18.52 through 18.56;

H.

Special building setback lines set forth in Chapter 18.58; and

I.

The off-street parking requirements set forth in Chapter 18.60.

(Ord. 2024-451 § 1 (Att. A), 2024; Ord. 2024-450 § 1 (Att. A), 2024)

Principal uses permitted in the M-U district shall be as follows:

A.

Uses permitted by Section 18.36.010;

B.

Single-family dwellings;

C.

Duplexes;

D.

Emergency shelters;

E.

Multi-family dwelling;

F.

Residential care facilities;

G.

Supportive housing;

H.

Transitional housing;

I.

Low barrier navigation centers;

J.

Publicly-owned parks, public schools, or other public buildings when located in conformance with the general plan;

K.

Temporary uses permitted by Section 18.36.030; and

L.

Any other use which is determined by the commission, as provided in Chapter 18.38, to be of the same character as the other uses permitted by this section.

(Ord. 2024-451 § 1 (Att. A), 2024; Ord. 2024-450 § 1 (Att. A), 2024)

The uses listed in this section shall be permitted only when a conditional use permit is granted as provided in Chapter 18.72:

A.

Uses permitted by Section 18.36.020;

B.

Administrative-professional planned unit developments as regulated by Chapters 18.44 and 18.72, provided any such development conforms to the floor area limitations of Section 18.54.052;

C.

Administrative and professional offices that meet the domestic needs of the residents of the town and its spheres of influence or which provide services to other businesses or institutions in the town or its spheres of influence meeting domestic needs, provided any such establishment conforms to the floor area limitations of Section 18.54.052;

D.

Medical and dental clinics, provided any such clinic conforms to the floor area limitations of Section 18.54.052;

E.

Physical therapy and fitness training, provided any such use conforms to the floor area limitations of Section 18.54.052;

F.

Veterinary clinics, provided any such clinic conforms to the floor area limitations of Section 18.54.052;

G.

Real estate and insurance offices, provided any such office conforms to the floor area limitations of Section 18.54.052;

H.

Uses permitted by Section 18.20.030.G; and

I.

Any other use which is determined by the commission, as provided in Chapter 18.38, to be of the same character as other uses permitted by this section, provided that a use found to be of the same character as another use must meet the floor area limitations of that use as set forth in Section 18.54.052.

(Ord. 2024-451 § 1 (Att. A), 2024; Ord. 2024-450 § 1 (Att. A), 2024)

Accessory uses permitted in the M-U zone shall be as follows:

A.

Accessory uses as permitted in Sections 18.36.040 and Chapter 18.42;

B.

Parking lot for passenger vehicles;

C.

Off-street loading spaces;

D.

Accessory uses permitted by subsections B, D, E, F, G, H, I, and J of Section 18.12.040; and

E.

Household pets permitted by town ordinances.

(Ord. 2024-451 § 1 (Att. A), 2024; Ord. 2024-450 § 1 (Att. A), 2024)

Table 18.23.050, Development standards—Mixed-use zoning district, establishes the development standards for the mixed-use zoning districts. The numbers in each illustration refer to corresponding regulations in the table that follows.

Figure 18.23.050: Development standards—Mixed-use zoning district.

Table 18.23.050: Development standards—Mixed-use district.

Notes:

1.

Development standards for 4394 Alpine Road may vary as established by the supportive housing overlay in the town of Portola Valley 2023-2031 Housing Element. See Housing Element Section 6, Adequate sites for specific standards.

2.

Development standards for 4370 Alpine Road are supplemented as set forth in the Town of Portola Valley 2023-2031 Housing Element. See Housing Element Section 6, Adequate sites for any additional specific standards.

3.

Building height on 4370 Alpine Road is limited to one story within fifty feet of the property line along Nathhorst Avenue.

(Ord. 2024-451 § 1 (Att. A), 2024; Ord. 2024-450 § 1 (Att. A), 2024)

A. Residential Building Design. The design standards of Sections 18.15.060.A through G, with the exception of the daylight plane standards of Section 18.15.060.A, which are modified per 18.23.060.B, apply to the following:

1.

All residential buildings in the M-U district; and

2.

All upper-story portions of residential mixed-use buildings in the M-U district.

B.

Interior Side Daylight Plane. The building envelope must fit within a plane which starts at the natural ground surface at the property line and increases in height at a ratio of two vertical units to one horizontal unit away from the property line.

C.

Site Design. The design standards of Sections 18.15.060.H through K apply to all development in the M-U district.

D.

Non-Residential Ground Floor Transparency. A minimum forty percent of ground floor street-facing non-residential facades between two-point-five and six feet in height shall be transparent window surfaces with no more than a five percent tint. Mirrored windows are not allowed.

Figure 18.23.060.D: Ground floor transparency.

E.

Entry Separation. Any shared or individual entrance to residential units must be a minimum of twelve horizontal feet from any entrances to non-residential uses.

(Ord. 2024-451 § 1 (Att. A), 2024; Ord. 2024-450 § 1 (Att. A), 2024)

A. All non-residential uses and structures, other than accessory buildings, shall be subject to site plan and architectural approval by the architectural and site control commission as provided in Chapter 18.64.

B.

Required conditions as stipulated by subsections A, B and C of Section 18.12.050;

C.

Conformance with the requirements set forth in Section 18.37.010.

D.

All uses shall be conducted within completely enclosed buildings except for:

1.

Delivery of fuel, lubricants, and minor incidental servicing of vehicles at service stations;

2.

Parking and loading spaces;

3.

Outdoor dining areas;

4.

Recreation facilities;

5.

Public utility electric substations; and

6.

Nurseries for propagation and sale of trees, plants, and shrubs.

E.

Processing, packaging, treating, and the incidental storage related thereto shall be in the same line of merchandise or service as the retail or service business conducted on the premises. The gross floor area occupied by the business to be devoted to such activities shall not exceed fifty percent and there shall be no more than three employees engaged in such activities.

F.

Amusement devices shall be permitted as accessory uses only when specifically set forth in an approved conditional use permit. Conditional use permits containing such accessory uses may be approved only for a specific applicant and such use permits are nontransferable.

G.

During hours when an establishment is not open for business, only security lighting shall be allowed. Such lighting, both inside and outside, shall be of the minimum amount and the intensity to achieve its intended purpose.

H.

The total net floor area devoted to office uses on any parcel shall not exceed fifteen percent of the net floor area of all uses on such parcel. When an application is for a conditional use permit, the planning commission may allow the net floor area devoted to office uses to be increased up to but not exceed fifty percent of the total net floor area. An increase above fifteen percent may be authorized when the planning commission finds that the larger percentage will allow the development to be more compatible with the site conditions and surrounding the development that could otherwise be achieved and will not unduly jeopardize the space anticipated to be required for commercial uses in the town. "Net floor area" is defined in Section 18.54.050.

I.

Properties identified on the flood insurance rate maps shall comply with the provisions of Chapter 18.32.

J.

Properties with historic resources as identified in the historic element of the general plan shall comply with the provisions of Chapter 18.31.

K.

This zoning district permits one hundred percent residential projects with no commercial component. Where the whole site is redeveloped, at least fifty percent of the floor area of development must be residential. Any non-residential development shall include a residential component at the minimum density specified in Table 18.23.050.

(Ord. 2025-453, § 1, 4-23-2025; Ord. 2024-451 § 1 (Att. A), 2024; Ord. 2024-450 § 1 (Att. A), 2024)