The Willdan Letter

Quarterly News for California Building Departments

Issue #48, Oct - Dec 2015

Did You Know?Tiny Houses on Wheels

tiny house on wheels

A tiny mobile house in Portland, OR. By Tammy (Weekend with Dee)" [CC BY 2.0], via Wikipedia Commons

Did you know there are standards applicable to tiny houses on wheels? And that their use may be restricted? It may be difficult to determine which standard applies and how a so-called tiny house may be installed for human occupancy.

Tiny houses on wheels have suddenly become the subject of magazine articles and cable television programs. We are to understand that the tiny house movement is something new. Truly it is not, and the popularity of trailers has come and gone before. Most tiny houses currently marketed have a transportation system including a hitch, tow bar, chassis and wheels. Following World War II, the use of trailers became in many regions a solution to the need for inexpensive housing. For many they were home while attending college on the G.I. bill. Over time small towable trailers evolved into Mobilehomes and later Manufactured Homes and Factory-Built Housing while those that remained towable with a motor vehicle are now forms of Recreational Vehicles.

So what is a tiny house and how can it be used? Well, that depends on its size and how it is equipped. We must look beyond the stylish architecture. California law establishes definitions that define various forms of housing. Most all housing is subject to regulations or building standards adopted by the California Department of Housing and Community Development (HCD). The determination as to the applicable standard can only be made by applying the definitions in state law.

First let's look at those towable behind a standard motor vehicle. Health and Safety Code (HSC) Section 18010 defines a recreational vehicle, which in short is a unit with or without motive power (motorhome, travel trailer, 5-wheel trailer), of less than 320 square feet excluding cabinetry, closets and the bathroom, and no more than 400 sq.ft. of gross area at maximum horizontal projection, that all can be moved as a single unit on the highways without a permit.

A Park Trailer is a recreational vehicle, specifically defined in HSC Section 18009.3, as a unit with up to 400 s.f. excluding any loft space and attached porches, and may be up to 14 feet wide needing a permit for highway movement. HSC Section 18033 provides specific standards for a Park Trailer loft, including design loads, stair rise and run, hand and guard rails. Park Trailers are subject to the ANSI Standard A119.5, and all other recreational vehicles are subject to ANSI Standard A1192, to which compliance is to be self-certified by the manufacturer.

There is no law in California providing for the installation of a recreational vehicle as an improvement to underlying real property. Recreational vehicles are to be installed in Special Occupancy Parks (see HSC Division 13, Part 2.3), commonly called recreational vehicle parks, or as may be allow by local zoning. For a recreational vehicle to be installed as a real property improvement, the local agency having jurisdiction would need to accept the unit as meeting the applicable building standards in Title 24, California Code of Regulations, adopted by HCD pursuit to the State Housing Law in HSC, Division 13, Part 1.5, beginning with Section 17910.

"Tiny House Giant Journey in the Petrified Forest and an RV" by Guillaume Dutilh - Own work. Licensed under CC BY-SA 4.0 via Commons.

If the tiny house does not fit the definition of a recreational vehicle, then it may be a manufactured home as defined in HSC Section 18007, or a Factory-Built Housing as defined in HSC Section 19971. Manufactured homes are subject to federal standards and must bear a label attesting to compliance with standards adopted by the U.S. Department of Housing and Urban Development. Factory-Built Housing must bear an insignia attesting to compliance with the building standards in Title 24, and supportive regulations in Title 25, California Code of Regulations, adopted by HCD. A manufactured home may be installed within a mobilehome park, or as with factory-built housing it may be installed on a foundation system as an improvement to underlying real property. The manufactured home must have a permanent chassis so it will come down the road on wheels just like a recreational vehicle. Factory-built Housing may or may not have wheels for transportation.

All these forms of housing can be made to look attractive and like conventionally built on-site housing. When a tiny house is proposed for installation and use, the local planning and building departments will need to make a determination as to the lawful means of installation and occupancy. First, determine what it is, then apply the state laws addressing the allowable installation for that type of housing form. Look to local land use ordinances, too

HCD has a booklet available on their website that provides clarification as to the differences between manufactured homes and park trailers.

Legislative Update

Bills of Interest to California Building Departments

California senat seats

September 11, 2015, was the last day the legislature could pass a bill and route it on to the Governor.  When a bill is sent to the Governor, it is called an enrolled bill, and the Governor has 30 days to approve, veto, or allow a bill to become law without the Governor’s action.

We have listed those bills separately that have been acted on by Governor from those bills that did not reach the Governor’s desk and will most likely continue in the legislative process during the 2016 portion of the 2015/2016 session. All listed bills have impact on building codes, the code adoption process, building designs, or local building departments.

Those bills that were approved by the Governor enact laws effective January 1, 2016.  Those bills vetoed by the Governor may be enacted by a 2/3 override vote of the legislature. 

Charging station

AB 1236 (Chapter 598, Statutes of 2015): This bill was signed by the Governor on October 8, 2015. The bill requires a city, county, or city and county with a population of 200,000 or more residents to adopt an ordinance, by September 30, 2016, that creates an expedited and streamlined permitting process for electric vehicle charging stations. A city, county, or city and county with a population of less than 200,000 residents must adopt the ordinance by September 30, 2017. The bill would require electric vehicle charging stations to meet specified standards.



AB 662 (Chapter 742, Statutes of 2015): This bill was signed by the Governor on October 10, 2015. It requires a commercial place of public amusement, as defined, constructed on or after January 1, 2020, or renovated on or after January 1, 2025, to provide and maintain at least one adult changing station with specified signage.

AB 764: This bill was vetoed by the Governor on October 6, 2015.  It had proposed to require the Building Standards Commission, in collaboration with the State Architect and the State Fire Marshal, to consider standards for the installation of vehicle barriers to protect persons within buildings, and pedestrians adjacent to buildings, from collisions into those buildings by motor vehicles. The Governor's veto message says this is a matter for local consideration.

SB 119: This bill was vetoed by the Governor.  It proposed to require the Department of Housing and Community Development and the California Building Standards Commission to develop building standards requiring all new residential and nonresidential non-pressurized building sewers that connect from buildings to the public right-of-way or utility easement to include the installation of tracer wire. The bill proposes requirements to be met before performing excavations.

SB 287 (Chapter 449, Statutes of 2015):  The Governor signed this bill on October 2, 2015.  It requires privately owned occupied buildings of Group A, B, E, F, I, M and R occupancies, with a specified occupancy load, to be equipped with an automated or automatic external defibrillator. 

The following bills did not reach the Governor’s desk this year and may possibly continue in the legislative process in 2016.

greywater in use sign

water meter

AB 307: The bill states the Legislature's intent to enact law regarding graywater recharge.  This generally means that amendments will be forthcoming, but there has been little activity since its introduction.  

AB 576: Proposes to authorize the Building Standards Commission to appoint individuals from the energy and resource efficiency professions to the Commission's Code Advisory Committees.  The bill states the legislature's intent to enact requirements to promote the creation of energy and resource efficient homes in California. 

AB 723:  After four amendments, proposes to require the lease or rental agreement for a single-family residential real property or any portion of a multifamily residential real property or commercial real property that is entered into, renewed, or amended after January 1, 2016, or January 1, 2017, respectively, to specify the property owner's intent to replace non-complying plumbing fixtures with water-conserving plumbing fixtures by specified future dates.  

AB 1005:  The bill states the intent of the Legislature is to encourage and support the widespread deployment of electric vehicles, and protect competitive markets for electric vehicle charging stations and equipment. 

AB 1013:  Proposes to require the California Energy Commission to approve and test any public domain computer program designed to enable design professionals, builders, and government officials to estimate energy consumed by a proposed residential or nonresidential building.  The test must verify the accuracy of such program six months prior to the effective date of any new or amended energy standard.

AB 1463: Proposes to require the State Water Resources Control Board, in consultation with the State Department of Public Health, the California Building Standards Commission, the Department of Housing and Community Development, and stakeholders, to establish water quality standards for systems using onsite treated water in internal plumbing of residential and commercial buildings.

SB 7: After five amendments, proposes to authorize the Department of Housing and Community Development to develop and propose for adoption by the California Building Standards Commission, building standards that require the installation of water submeters in multiunit residential buildings.

What's Up with the State?

News on Code Adoption, State Agencies & More

California capital

CALIFORNIA BUILDING STANDARDS COMMISSION (CBSC) continues to administer the 2015 Triennial Code Adoption Cycle that will result in the publication of the 2016 edition of the California Building Standards Code in Title 24, California Code of Regulations.

Here is a description of the most recent and future activities.

  • The last of six CBSC Code Advisory Committee meetings was held on Sept. 10, 2015. The CACs have provided recom­men­da­tions to the state proposing agencies. The state proposing agencies in turn have completed their consideration of the CAC recommendations, or are in the process of doing so.
  • The Division of the State Architect is the first to present their final proposals in a 45-day public comment period. Others will follow soon as all the state proposing agency proposals in final form after the 45-day public comment period are scheduled to be received by the CBSC on or before November 15, 2015, according to CBSC's posted timeline. Each of the state proposing agencies must issue a Notice announcing the 45-day public comment period, with details on the nature of the proposal and how to obtain the regulatory language (called Express Terms).
  • Following all the 45-day public comment periods by each of the state proposing agencies they must consider public comments and possible amendments to the proposed building standards. Additional public comment periods will follow if amendments are made.

The agenda for the October 21, 2015, meeting of the Building Standards Commission includes previously adopted emergency building standards by the CBSC, Department of Housing and Community Development, Division of the State Architect, and Office of Statewide Health Planning and Development relating to outdoor irrigation systems. The proposal is to readopt the emergency building standards to allow more time to finalize the building standard. Additional emergency building standards relating to outdoor water efficiency will also be considered for adoption in order to remove conflicts with Title 20 standards adopted by the California Energy Commission.

  • The CBSC has scheduled a two-day meeting to occur on December 16 and 17, 2015, to consider adoption of all the proposed building standards, including the newest editions of the model codes. The agenda is not yet available so watch the CBSC website.
  • The timeline and rulemaking documents are available at the CBSC website. The state proposing agencies must also make the rulemaking documents available on their respective websites.

Division of the State Architect (DSA) has posted its Summer/Fall 2015 newsletter, called the CASp Report. It includes information in 8 pages about the CASp program, code requirements, and information relating to accessibility building standards.

The DSA has nearly completed the rulemaking to amend the Certified Access Specialist program (CASp) regulations in Title 21, California Code of Regulations. Adoption of the proposed regulations may be announced soon. Watch this DSA web page for the announcement.

Dates, Links & an Acronym Cheat Sheet

Important Dates

Oct. 14, 2015: CASp examination by the Division of the State Architect for those reg­is­tered by Sept. 14, 2015. Details at DSA website.

Oct. 21, 2015: California Building Standards Com­miss­ion public meeting: agenda. Tele­conf­erence Num­ber: (888) 431‑3632; Participant Code: 9421328. Webcast (YouTube)

Oct. 26-28, 2015: County Building Officials Association of Cali­for­nia, Annual Business meeting in Yosemite: Details.

Oct. 26-29, 2015: CALBO Education Week, in Ontario, CA. Details at CALBO website.

Dec. 16-17, 2015: Two day CBSC meeting to consider adoption of the 2015 Triennial Code Adop­tion Cycle pro­posals for the 2016 edition of the California Building Standards Code to be located in Title 24, California Code of Regulations.

Useful Websites

Title 24 online

State Laws

Legislative Bills

Building Standards Commission

Dept. of Housing and Community Development

Office of the State Fire Marshal

Division of the State Architect


  • CAC: Code Advisory Committee, used by the California Building Standards Commission.
  • CBC: California Building Code in Title 24, California Code of Regulations
  • CBSC: California Building Standards Code, or California Building Standards Commission, depending on the use and context. 
  • CCR: California Code of Regulations
  • CFR: Code of Federal Regulations
  • HSC: Health and Safety Code (a California state law)
  • NOPA: Notice of Proposed Action, a required rulemaking document announcing a proposed adoption of a regulation, including a building standard, along with information as to the nature of the proposal, any scheduled hearing, and how to obtain the proposed regulatory language and how to submit comments.
  • ET: Express Terms, a required rulemaking document providing proposed regulatory language. 
  • ISOR: Initial Statement of Reasons, a required rulemaking document used to provide the rationale for a proposed regulation, including a building standard.
  • FSOR: Final Statement of Reasons, a rulemaking document used to provide the final discussion and rationale for a proposed regulation, including a building standard, that is in final form and up for adoption. 

Other News & Things to Remember

DSA has announced the following tentative 2016 schedule for Certified Access Specialist program (CASp) examinations.

  • February in Oakland and Los Angeles;
  • June in Fresno, Sacramento and Los Angeles;
  • October in Sacramento and Los Angeles;
  • Watch this DSA page for the announcement of the specific dates and registration deadlines.

All the Title 24 codes are available online at the California Building Standards Commission website.

To obtain the Title 24 Supplements that became effective on July 1, 2015, go to the Building Standards Commission Current Codes page. All published Supplements and Errata issued to date for the 2013 edition of Title 24, California Code of Regulations, are available at this site. Bookmark this webpage for your future use. It is best to sign up for supplements and errata issuances from the code publishers using the registration card that comes with each Title 24 binder.

To receive notices from the California Building Standards Commission of proposed building standards, including emergency building standards, their newsletter, and Information Bulletins, sign up at the Commission's website.

California Commission on Disability Access (CCDA) provides a Construction Inspection Checklist, 2015 edition.

Photos inspected or plan-checked by Willdan.