Chapter 20.91 — TWO-UNIT PROJECTS IN SINGLE FAMILY ZONES

A. It is the intent of these regulations to provide opportunities for two units on one legal parcel in the RS Zoning District, consistent with state law and local regulations. In the event of an inconsistency between this chapter and Government Code Section 65852.21, Government Code Section 65852.21 shall prevail.

B. A two-unit project shall not be permitted under this chapter in any of the following
circumstances:

1. Parcels located in:

a. The coastal zone;

b. Wetlands;

c. Very high fire severity zones, except if the site has adopted fire hazard
mitigation measures pursuant to existing building standards or state fire
mitigation measures applicable to the development;

d. A hazardous waste site, unless site has been cleared by the state for residential
use;

e. Delineated earthquake fault zones, unless the development complies with
applicable seismic protection building code standards;

f. Special flood hazard areas (100-year flood zones), unless the site has been
subject to a FEMA Letter of Map Revision issued to the City or the site meets
FEMA requirement necessary to meet minimum flood plain management
criteria of the National Flood Insurance Program;

g. A regulatory floodway identified in a FEMA map, unless the development has
received a no-rise certification;

h. Lands identified for conservation in an adopted natural resource protection plan,
habitat for protected species, or under a conservation easement; and

i. A historic district or property designated pursuant to a local ordinance or
included on the State Historic Resources Inventory.

2. The proposed development would require demolition or alteration of any of the
following types of housing:

a. Housing that is subject to a recorded covenant, ordinance, or law that restricts
rents to moderate, low, or very low incomes;

b. A rent controlled unit;

c. A unit that has been occupied by a tenant within the past three years;

d. Housing units removed from the rental market within the past 15 years under the
Ellis Act.

3. The proposed development would result in the demolition of more than 25% of the existing exterior structural walls, unless the site has not been occupied by a tenant in the last three years. 4. The building official finds that the proposed development would have a specific, adverse impact on public health and safety or the physical environment that cannot be feasibly mitigated or avoided. (Ord. 1331 § 2, November 15, 2021)

A. General Requirements. A proposed two-unit project shall comply with the following requirements:

1. A two-unit project shall be considered a permitted use on a parcel in the RS Zoning
District, subject to the requirements of this chapter.

2. A two-unit project located in the floodplain shall comply with Title 18 of this Code.

3. If the construction of a two-unit project is proposed within 30 feet of the top of the
bank for any watercourse identified in Chapter 20.76, the applicant shall provide the
Building Department with all applicable permits from outside agencies, including, but
not limited to, the San Francisco Bay Regional Water Quality Control Board,
California Department of Fish and Wildlife, the Army Corps of Engineers, State
Water Resources Control Board and/or U.S. Fish and Wildlife Service.

4. A permanent address is required for each dwelling unit.

5. Prior to receiving a building permit, the local water or sewer agency shall submit
letters of service availability for water and sewer disposal to the Building Official.

6. Any two-unit project legally created shall be governed by the zoning regulations in
effect at the time of approval.

B. Restrictions. A qualifying two-unit project shall be subject to the following restrictions:

1. The development and use of the dwelling units shall only be valid and permitted based
on the terms established in the chapter.

2. The dwelling unit(s) shall not be rented for a period of less than 30 consecutive days.

3. Any owner wishing to modify the number of units must request termination of a
dwelling unit under this chapter, satisfying all zoning and development standards such
as setbacks, floor area and lot coverage.

4. The owner and all successors in interest in the subject property shall agree to respond
to any City of Mill Valley survey of owners of all dwelling units to determine use,
code consistency and for reporting purposes to the State Department of Housing and
Community Development (HCD).

5. The owner and all successors in interest in the subject property shall maintain the
dwelling units in accordance with all applicable regulations established in this
chapter. Violations and lack of compliance with any provisions of this section may
result in legal action against the property owner, including revocation of any right to maintain the dwelling units on the property as outlined in Sections
20.91.050—20.91.060, and shall be subject to administrative fines and penalties as
contained in Chapter 8.02 of the Mill Valley Municipal Code.
(Ord. 1331 § 2, November 15, 2021)

A. Two-Unit Projects Subject to Ministerial Planning Director Approval.

1. The Planning Director or his or her designee shall ministerially review and approve a
two-unit application and shall not require a public hearing, provided that the
submitted application is complete and demonstrates that the two-unit project complies
with the requirements contained in this Title 20 and qualifies under Government Code
Section 65852.21(a).

2. Where a qualified two-unit application is submitted with an application for other
redevelopment work that is subject to design review under Chapter 20.66, the
application will be considered separately without discretionary review or a public
hearing, following action on the portion of the project subject to Chapter 20.66.

3. In addition to obtaining planning approval for the two-unit project, the applicant shall
be required to obtain a building permit, tree removal permit if applicable, and other
applicable construction permit requirements prior to the construction of the dwelling
units.
(Ord. 1331 § 2, November 15, 2021)

Proposed two-unit applications that comply with Government Code Section 65852.21 are subject to the development standards in this section and the objective design guidelines established in the City of Mill Valley's single family design guidelines, as adopted and amended from time to time.

A. Development Standards.

1. A two-unit project shall conform to all objective zoning, subdivision, and design
standards applicable to the RS Zoning District, except as expressly provided in this
chapter. Notwithstanding the above, if the application of an objective standard would
require one or both units to be less than 800 square feet, such standard shall be waived
to the extent necessary to allow construction of a unit(s) of at least 800 square feet.

2. See Section 20.16.040(A) for adjusted floor area allowances, except as follows: those
parcels that are less than 6,000 square feet may not apply deductions under Section
20.16.040(A)(1)(b).

3. Maximum height of a two-unit project is 25 feet above natural grade to the highest
point of the roof. Buildings may be built up to 35 feet within the lot area, should the
two units be consolidated within one structure and comply with the allowable
setbacks granted under the single family zoning district.

4. Maximum lot coverage is based on Section 20.16.040(D), which includes the total
footprint of all structures, including, but not limited to, the Duplex, garage, all accessory buildings and decks over 18 inches above grade.

5. A two-unit project shall include two primary dwelling units where either:

a. Both units are greater than 1,000 square feet; or

b. The square footage ratio between the two units are no greater than 2:3 (for
example, if one unit were 900 square feet, the other would need to be at least
600 square feet).

6. One-bedroom dwelling units may not exceed 850 square feet of gross floor area.

7. Useable outdoor living space shall be split equally between each unit. Areas paved
for the storage or movement of motor vehicles or bicycles cannot be considered
usable outdoor living space.

8. Front exterior yard setback shall be 15 feet from the street property line, with
exemptions granted for parking structures on sloped lots, see Section 20.60.080.

9. Setbacks from the side and rear lot property lines shall be no less than four feet, except in the case of existing structures or structures constructed in the same location and to the same dimensions as an existing structure. Double frontage and corner lots shall use the following criteria to determine rear and side yard setbacks. a. Double frontage, through lots shall maintain a front exterior yard setback for the primary frontage containing either the driveway encroachment or in association with the orientation of the home. The opposite frontage shall be considered the rear yard. b. Corner lots with frontage on two streets shall maintain a front exterior yard setback for the primary frontage containing either the driveway or orientation of the home. The remaining street frontage shall be considered the side yard.

   B. Building Form.

   1. Dwelling units shall include permanent provisions for living, eating and sleeping,
   including a kitchen and bedroom closet or other storage.

   2. Dwelling units shall have separate exterior entries facing the street and may not have
   an internal connection between units.

   3. A permanent foundation shall be required.

   C. Off-Street Parking.

   1. One off-street parking space is required per dwelling unit, unless the parcel is located
   within one-half mile of a high-quality transit corridor as defined in subdivision (b) of
   Section 21155 of the Public Resources Code or major transit stop as defined in
   Section 21064.3 of the Public Resources Code or there is a car share vehicle located
   within one block of the parcel.

   2. The location of the required parking space(s) shall not obstruct the required parking
   of each dwelling unit and shall be a minimum of 20 feet in length.

   3. Tandem parking is prohibited between units.

   4. The required parking spaces must be covered and may encroach in the within the front
   setback based on Section 20.60.080.
   (Ord. 1331 § 2, November 15, 2021)

A. No building permit shall be issued to remove permanent features of the two-unit project, including the provisions for eating, cooking and sanitation, and separate exterior entrance until written approval to terminate the use of living space is granted by Planning Department.

B. At its discretion, the Planning Director may grant an owner's written request to terminate
the use of a dwelling unit. The planning director shall consider the length of time such
permit has been in force, the conditions of approval, the exceptions granted for the duplex,
and the impact on the City's affordable housing supply.

C. As a condition of termination, the Planning Director shall require the owner to make
modifications to the property to comply with: (1) current building code requirements; and
(2) current development standards in effect at the time the request is made to terminate use,
including, but not limited to, setbacks, heights, parking and adjusted floor area. The owner
shall apply for a building permit to make such modifications as required by the City's
building and fire codes.

D. In no case shall the dwelling unit be terminated, if the proposed termination would require
a variance to exceed adjusted floor area for the single family dwelling unit.
(Ord. 1331 § 2, November 15, 2021)

A. It is unlawful for any person to violate any provision or to fail to comply with any of the requirements of this chapter. A property will be found in violation of this chapter when the dwelling unit has been created without the required City approvals or does not comply with standards and deed restrictions established in this chapter. Violations are subject to the enforcement penalties and procedures of Chapter 8.02 of this Code.

B. In addition to the enforcement penalties and procedures included in Chapter 8.02 of this
Code, the City may pursue any remedies provided by law against the owner found to be in
violation of this chapter, or a property not maintained in conformance with this chapter
including:

1. Revocation of the livable space as two-units;

2. Where a dwelling unit has been improperly terminated and is being used as habitable
space for a single primary dwelling unit, removal of the floor area serving as habitable
space may be required; and

3. In any civil enforcement action, the City is entitled to recover attorneys' fees and costs
from an owner who is determined to have an illegal dwelling unit or is in violation of
this chapter.
(Ord. 1331 § 2, November 15, 2021)