8-1-1 Temporary Occupancy of Travel Trailers, Recreational Vehicles, and Transportable Housing Units (Tiny Homes)

To provide a permit process for the temporary occupancy of travel trailers, recreational vehicles, and Transportable Housing Units as defined by the California Building Code and to ensure compliance with applicable zoning, building and health codes.

Travel trailers, recreational vehicles (RVs), and Transportable Housing Units (tiny homes) must meet California Building Code requirements, including code compliant plumbing and electrical service connections. Each of the listed occupancies must either be connected to a parcel’s septic/sewer system or an applicant may provide a copy of an executed contract for hold/pump and haul services for the duration of the temporary occupancy permit. Providers of pump and haul services must be licensed in the State of California to provide those services.

1. The parcel where the temporary unit is proposed shall be at least six thousand (6,000) square feet in size.
2. The temporary unit shall meet zoning setback requirements, scenic resource (SR) requirements, existing building envelope restrictions, and, where applicable, have approval from the board or specific plan-designated design review committees.
3. The temporary unit shall have approved utility connections:
   1.  For wastewater to an existing or proposed septic system or sanitary sewer system, except that:
      1. For units that are not agricultural employee units, hold and haul services for domestic waste may be substituted for connection to an existing septic or sewer system, where (1) the hauler is in compliance with all state law requirements, including holding a valid registration issued by the California Department of Toxic Substances Control for the transport of hazardous wastes, and (2) the applicant provides the Department a copy of the executed contract for the hold and haul service for the duration of the temporary occupancy with its permit application.
      2. For units that are agricultural employee units, all sewage from the units shall be discharged into a lawful sewage disposal system, unless otherwise approved by Permit Sonoma.
   2. For potable water to an existing well or a public water system.
   3. The temporary unit shall have an approved electrical and/or gas source per the model California Residential Code.
      1. If new underground or overhead utilities are required to serve the temporary structure, a separate Building Permit (BLD) shall be required for installation and inspection of these elements.
4. Annual renewal of temporary permits is required, subject to application and approval.
   1. An application for renewal of TEM permits must be submitted 30 days prior to expiration of the current term.
   2. An applicant seeking renewal of a TEM permit reliant on a hold and haul contract in lieu of connection to on-site septic or sewer systems must provide proof of unbroken service from the servicing contractor over the prior year, as well as a contract for the proposed renewal permit term.
5. Upon expiration of a TEM permit and no timely application for renewal:
   1. The temporary unit must be disconnected from utilities within 60 days of the permit’s expiration date and residential use of unit must cease accordingly. For units served by a holding tank, this includes obtaining a new tank destruct permit (SEP) per Onsite Wastewater Treatment System (OWTS) manual Section 5.2.A.
   2. Within 60 days of the permit expiration date, or following required disconnection of utility service, whichever occurs earlier, a temporary unit must be removed from the property, unless such storage of the disconnected and unoccupied unit is permitted under Chapter 26 and all other applicable laws.
6. Temporary units must comply with Fire Safe Standards, including but not limited to access and setbacks for temporary units that are 640 square feet or larger or as otherwise may be required.

Temporary Occupancy of Travel Trailers, RVs, & Transportable Housing Units (Tiny Homes) May Be Permitted for the Following Purposes:

1. Temporary occupancy of a travel trailer, recreational vehicle, or Transportable Housing Unit is permitted during the construction or major remodeling of a single-family dwelling, subject to the following requirements:
   1. A building permit for either a new single-family dwelling or for the major remodeling of an existing single-family dwelling must be ready for issuance.
   2. Temporary occupancy permit is valid for 1 year or until the expiration of building permit(s), whichever is sooner.
   3. Removal of the temporary unit or disconnection from utilities is required prior to receiving a final inspection on the building permit(s). A disconnected temporary unit may remain on site only if storage of the disconnected and unoccupied unit is permitted under Chapter 26 and all other applicable laws.
2. Temporary occupancy of a travel trailer, recreational vehicle, or Transportable Housing Unit prior to the application of a building permit for or construction of an Accessory Dwelling Unit (ADU) is permitted subject to the following requirements:
   1. The subject parcel must be located where ADUs are allowed by the primary and combining zoning districts and as defined in Section 26-88-060. These temporary units are not allowed in the Z Accessory Dwelling Unit Exclusion combining districts.
      1. Temporary ADU unit maximum floor area shall be one thousand two hundred (1,200) square feet.
   2. A temporary unit may be allowed prior to the construction or application for a building permit for a permanent ADU.
   3. Once construction or a building permit for a permanent ADU is underway, removal of the temporary unit or disconnection from utilities is required prior to receiving a final inspection on the building permit(s). A disconnected temporary unit may remain on site only if storage of the disconnected and unoccupied unit is permitted under Chapter 26 and all other applicable laws.
3. To house an ill, convalescent or otherwise disabled friend or relative needing care from the occupant of the primary residence; or a friend or relative providing necessary care for an ill, convalescent or otherwise disabled occupant of the primary residence, subject to the following requirements:
   1. Documentation from a physician.
   2. The number of caregiver units is limited to one per legally established primary dwelling unit.
   3. The temporary caregiver unit shall not be rented, let or leased.
   4. No more than two (2) people may occupy the travel trailer or recreational vehicle.

Temporary Occupancy of Travel Trailers & RVs May Be Allowed for the Following Purposes:

1. To house agricultural employees for ninety (90) days, subject to the requirements of Sec. 26-24-060 and the following:
   1. Allowed units: travel trailers and RVs.
   2. No more than one (1) camp per property with up to four (4) vehicles and/or travel trailers.
   3. Must be on properties with a Bonafide agricultural operation.
   4. All sewage from these temporary units shall be discharged into a lawful sewage disposal system, unless otherwise approved by Permit Sonoma.
   5. Recreational vehicles and/or travel trailers must be immediately removed from the site when it is no longer occupied by agricultural employees.

• Sonoma County Code Sections 26-88-010(p) and 26-24-060, 7-13
• Sec. 21 of the Sonoma County Onsite Wasterwater Treatment (OWTS) Manual

The Building Official shall have the authority to render interpretations of the code and adopt and enforce rules and supplemental regulations to clarify the application of its provisions per Section 104.2.1 of the California Building Code and Section R104.1 of the California Residential Code.

1. Applicant submits the following electronically:
   1. A completed temporary permit application;
   2. A complete site plan;
   3. Electrical and sanitation connection details, or a contract for hold and haul services with a California State Licensed contractor for the duration of the temporary permit period (generally 1 year), and evidence of past services if required for a renewal application;
   4. Floor plans;
   5. Installation manuals for mobile homes and state-approved manufactured homes as applicable; and,
   6. Exit stairs and deck detail, if required.

   Only complete applications will be accepted. All plans for Recreational Vehicles, Travel Trailers, Manufactured Homes, and Transportable Housing Units shall comply with the State of California requirements for such.

2. Permit Technician verifies the address and obtains the purpose of the unit, verifies parcel is at least 6,000 square feet in size, initializes a TEM permit selecting the appropriate subtype and then routes the file for review.
   
   Note: One or more temporary units may be allowed per parcel, subject to the requirements of Sec. 26-88-010(P). Travel trailers, recreational vehicles, and Transportable Housing Units on tires may be allowed on properties located in a F2 (Floodplain) zoning district due to the foundation requirements imposed under FEMA regulations. Mobile homes may be allowed in the F2 zoning district if they are elevated above the base flood elevation (BFE). No occupancy of travel trailers, motor homes, recreational vehicles, or Transportable Housing Units is allowed in the F1(Floodway) overlay area.
   (Refer applicant to Stormwater staff for questions.)
   1. If underground or overhead utilities are proposed to serve the temporary unit, the Permit Technician shall direct the applicant to apply for a separate Building Permit (BLD) application prior to acceptance and routing of the TEM application.
3. Zoning Approval: Planner confirms the purpose of the temporary unit, informs the applicant of zoning requirements and verifies compliance with Sec. 26-88-010(P) or Sec. 26-24-060 for the temporary use of trailers or recreational vehicles to temporarily house agricultural employees. The unit must meet zoning setback requirements, building envelope restrictions, and applicable scenic resource requirements with approval from any required board or specific plan designated design review committees.
   1. If the temporary unit is for temporary occupancy while constructing or remodeling a single-family dwelling, the planner verifies that a building permit has been issued for construction or major remodeling. A hold on final occupancy must be placed on that building permit until the temporary unit is removed or disconnected from utilities.
   2. If the temporary unit Is being used in advance of construction of an ADU, the planner will verify the parcel’s zoning allows for ADUs. If construction or a building permit for a permanent ADU is underway, a hold on final occupancy must be placed on that building permit until the corresponding temporary unit is removed or disconnected from utilities.
   3. If the temporary unit is to house a caregiver or person requiring care from the occupant of the property, the applicant is advised that the permit cannot be issued without a medical statement.
   4. If the temporary unit is to house agricultural employees, the planner will verify that a Bonafide agricultural operation exists on the property and advises the applicant that the permit is only valid for 90 days. Transportable Housing Units (Tiny Homes) are not allowed to house agricultural employees.

      Once the above are verified, the planner may provide Planning clearance on the electronic permit record, noting the temporary use and that all above requirements are met.

4. Well/Septic Approval:
   1. For temporary units during construction, as caregiver units, or ADUs, Well and Septic staff will verify the septic system has been installed, a final inspection of the septic system has been approved, and a valid Operational Permit is in effect when required. If all applicable criteria is affirmed, then septic approval shall be provided on the TEM. If all applicable criteria is not affirmed, then septic approval shall not be provided on the TEM.
      1. If the septic system record on file shows that the septic system has adequate capacity or if there is a record of the septic system and the applicant agrees to temporarily reduce sewage flow while the temporary trailer is on site. Flow reduction would include temporarily ceasing use of a bedroom while the temporary trailer is in use. A conditional statement on the TEM permit will be required for septic approval. If there is no record of the septic system, a findings report prepared by a qualified consultant identifying the capacity and adequate performance of the septic system shall be required. Generally, the septic system must be uncovered for evaluation. If the septic system is inadequate or if the house is served by a cesspool, a new septic system will be required meeting current OWTS Manual standards.
      2. Alternatively, an applicant may provide a hold/pump and haul contract with a state-licensed contractor for the duration of the TEM permit period (generally one year).
   2. For temporary housing of agricultural employees, unless a legal sewage dump station exists on the property, a Code Compliant or Non-Conforming septic system is required. Sizing of the system is based upon 40 gallons per person per day. If housing is only occupied in the summer, wet weather groundwater determinations may be waived by an approved formal variance complying with current OTWS Manual requirements. A conditional statement on the TEM permit will be required, which acknowledges the reduction in septic system sizing and any variances that are approved.
   3. For Applications Relying on a Hold/Pump and Haul Contract In Lieu Of Connection to a Site’s Septic or Sewer:
      1. Compliance with the OWTS Manual is required. This includes maintaining all setbacks for proposed new holding tanks and/or transmission lines.
      2. If the applicant intends to install a Holding Tank for a Hold and Haul contract, a septic permit for the tank must be obtained. The SEP permit application package shall be in conformance with requirements for septic or sump tanks per the OWTS manual in effect at the time. Well and Septic clearance shall not be granted for the TEM permit until the septic permit has been issued.
         1. Holding tanks shall be watertight and adhere to all required setbacks as required by the OWTS Manual section 8.1.A. and Table 7.2.c.
         2. Holding tanks must be installed below ground and shall be protected from vehicular traffic or must be a traffic-rated tank.
         3. Gravity flow from the unit to the holding tank is required unless pumping is included in accordance with the OWTS manual.
         4. Use of a temporary holding tank requires that a contract for regular pumping of the sewage be set up with a licensed septic pumping company, and the frequency of pumping specified in the contract shall be sufficient such that the holding tank will not overflow between pumping.
         5. Adequate storage is needed to protect public health from overflows onto the surface of the ground or back into the structure and to lower pumping costs. Sizing the temporary holding tank shall be based on a daily flow of approximately 53 gallons per day with a minimum tank size of 375 gallons, which corresponds to a pumping frequency of once per week (every 7 days). Unless a manufacturer-installed holding tank on an RV is 375 gallons in size, a separate holding tank with a minimum size of 375 gallons is required. Although 375 gallons is the minimum size allowed, it is recommended that the holding tank be at least 750 gallons (in concurrence with Section 8 of the OWTS) to minimize pumping frequency and associated higher operating costs for the homeowner. The holding tank shall be an IAPMO (International Association of Plumbing and Mechanical Officials) approved tank suitable for the storage of sewage. The following table denotes different tank sizes, and the corresponding pumping frequency required to be specified in the pumping contract:
            
            

            Temporary Holding Tank Size	Pumping Frequency
            375 Gallons	Once per Week (7 Days)
            750 Gallons	Once per 2 Weeks (14 Days)
            1200 Gallons	Once per 3 weeks (21 Days)
            1500 Gallons	Once per 4 weeks (28 Days)

         6. Per OWTS Section 8.5, tanks require 200 gallons of storage above the float that activates a high-water alarm. Although recommended, the requirement for a float and alarm can be waived, provided a contract with a licensed pumping contractor is in place that specifies an adequate pumping frequency based on the holding tank size as specified in the table above.
      3. If the permit is a renewal and the applicant has used a hold/pump and haul contract in lieu of connection to the site’s septic or sewer services, they must provide a demonstration of unbroken service for the duration of the prior term in addition to a new contract with a state-licensed contractor for the duration of the TEM permit period.

      Upon submittal of a complete application, Well and Septic staff shall provide septic approval on the TEM.

5. Public Sewer Approval: When use of public sewer under Sonoma Water jurisdiction is proposed, a sewer permit is required to approve a temporary unit. Permit Sonoma Engineering staff will inspect the sewer connection. Final approval of the sewer permit is required prior to occupancy of the temporary unit. When use of a sewer outside of Sonoma Water jurisdiction is proposed, a will-serve letter must be provided by the sewer service provider.
6. Plan Check Approval: The Building Division Plan Checker will: a) review electrical, plumbing and setup details; b) determine if an exit deck (36" x 36" minimum with stairs to grade) is required; c) verify that all creek and property line setback requirements and occupancy separations are met; d) provide the applicant sample drawings for setup, plumbing, and septic connections; and, e) complete the approval by providing any conditions on the building permit in the electronic permitting system.
7. Code Enforcement Approval: The Code Enforcement inspector will review the permit if there is an active violation on the property or if the temporary unit has been placed on the property before a permit has been issued. Civil penalties will be calculated and imposed if the permit is being submitted to legalize an existing illegal travel trailer, recreational vehicle, mobile home, or Transportable Housing Unit on the property. The Code Enforcement inspector may impose conditions on the permit.
8. Permit is Issued: The permit will be issued if all required approvals are obtained. A new address under the “Temporary” subtype will be issued for the caregiver and units installed in advance of an ADU. Units installed during construction of a primary home may be assigned the primary address until such time as the primary house is built. At this time, the permit technician will remind the customer that the address may change upon completion of construction of the residence or permanent ADU if access to the residence, locations, etc., change from the time of TEM permit issuance. Online applications will be processed through the typical intake, routing, review and approval process. If a paper application is accepted, it will be scanned into the appropriate electronic project record. The applicant is instructed to call for inspection(s), just like any other building permit, including final inspection.
9. Permit Fees.
   1. Mobile home setup.
   2. Minimum electrical.
   3. Minimum plumbing.
   4. Minimum zoning clearance.
   5. Well/Septic office clearance fee or hourly rate for field clearance.
   6. Applicable public sewer fees as may be required. (See Sanitation staff.)
   7. Addressing Fee.
10. Annual Renewal. Extension of a Temporary Occupancy (TEM) Permit for an additional year requires applying for and obtaining a renewed permit. If renewal is sought for an existing permitted temporary unit, the applicant is required to submit a completed temporary permit application and, where applicable, a medical statement from a physician. A permit technician will initialize the renewal permit, using the procedure listed for a new permit. No inspections are required.
11. Tracking for Temporary Occupancy (TEM) Permits. Department of Information Systems (DIS) Staff will produce reports from the permit processing system, including applicable permit Sub types prior to the expiration of the permit and forward them to designated staff. As a courtesy, assigned staff will mail letters to advise the property owner(s)/applicant of the requirement to renew their annual permit. Application and other materials will be included with the letter. The permit requirement is not waived or excused where the County does not send such courtesy reminder letters.
    Designated staff will continue to track permitted temporary units and submission of renewal applications. If the application is not submitted within the specified period of time or if the permit is not renewed, a copy of the letter may be referred to Code Enforcement, which may follow up with a Notice of Violation and proceed with an abatement action to require removal of the trailer or legalization through the permit process.

Notice of Pending Expiration of Temporary Permit (Example) (PDF)

Approved By:  Tennis Wick, Director

Reviewed By Department Manager:  Brad Cannon, Building Division Manager

Reviewed By County Counsel:  Jennifer C. Klein, Chief Deputy County Counsel

Lead Author:  Wil Lyons, Planner

Version: 04/24/2025, 10/20/2023, 03/01/2007