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Breakthroughs: Successful Local Strategies for Affordable Housing
Volume 3, Issue 4

Sign on side of brick building advertising available senior housing.

Non-Conforming Uses – A Source of Affordable Housing


Much of the affordable urban housing stock today is located in transition areas that are no longer primarily residential in nature. In many communities, the local government officials, seeking to discourage people from living in areas that are becoming industrialized or commercialized, have designated older residential structures in these areas as “non-conforming uses”. Most communities use their zoning code to limit the use of non-conforming use or building construction by limiting an owner’s ability to rebuild the structure if it has been damaged or destroyed, reoccupy a building that has been abandoned, or expand the use or the building itself. Recognizing that these restrictions could result in the loss of increasingly scarce private affordable housing, many communities have undertaken reforms to preserve this source of affordable housing.

Replacing Damaged/Destroyed Nonconformities

One way local governments can encourage the continued use of nonconforming residences is to allow reconstruction of the building in case of damage or destruction. Broward County, Florida requires uses with damage exceeding 51 percent to be brought into compliance, but exempts multi-family residential buildings in multi-family residential districts that exceed maximum density allowances. Salt Lake City maintains a strict 50 percent requirement for nonconforming uses, but defines most single-family detached dwellings, two-family dwellings, or twin homes as legal conforming uses, even though they might otherwise be considered nonconforming.

Lewiston, Maine increases the limit on the amount of damage or destruction that can occur before the unit has to be brought into compliance to 80 percent of the market value of the structure. For residential structures in shore land areas, the damage limit remains at 50 percent. Lewiston authorities also require that reconstruction commence within one year and be completed within two years of the original destruction. Santa Ana, California allows owners of damaged or destroyed buildings to restore the structure if the cost of repair does not exceed the building’s previous fair market value.
New Orleans authorities allow legally nonconforming uses to be restored regardless of the amount of destruction or damage.

San Diego approaches the reconstruction of nonconforming uses differently. The City defines these types of uses as “previously conforming uses” not “nonconforming uses”. Under these circumstances, the City allows the reconstruction of previously conforming residential uses subject only to the review process required for conforming structures. Restoration of nonresidential previously conforming structures face much stricter regulation.

Improving or Enlarging Nonconformities

Local governments can also encourage the continued use of nonconforming residential uses by allowing improvements and expansions. While most governments allow – and often require – maintenance of these properties, some regulate and restrict improvements and enlargements to the property. Salt Lake City does not allow a nonconforming use to be enlarged or extended to occupy a part of another structure or site that it did not occupy on or before April 12, 1995. Broward County allows owners to expand a nonconforming use of a building to any part of the building “clearly designed for such use”. Santa Ana allows structural alteration and enlargement of both single and multi-family nonconforming housing as long as the construction creates no new nonconformities. For multifamily units, the city requires that the owner comply with any existing off-street parking requirements in order to increase the number or size of bedrooms in the structure. For single-family housing, the number of dwellings on the property cannot be increased. San Diego allows owners to expand or enlarge a previously conforming structural envelope, but requires a “Neighborhood Development Permit” if the structure does not comply with applicable zoning regulations as to density or use. Lewiston allows such structures to be repaired and maintained. They also allow the building code official to issue a building permit for enlarging or adding accessory structures without a variance under certain conditions that are contained in the code.

Resuming a Discontinued Use

Relaxing restrictions on resuming a discontinued use is another avenue local governments can pursue to encourage the use of such buildings for housing. In Broward County, owners who have discontinued the nonconforming use for six or more months cannot recommence using the building for a nonconforming use. In Lewiston, owners have up to 12 months to resume an abandoned use. However, even then, the owner must secure a conditional use permit from the City’s board of appeals. The authorities in San Diego allow owners to resume a use if it has been discontinued for less than two years. The City also allows uses that have been discontinued for more than two years to resume; however, the owner is subject to City review of the request.


The cities above have adopted progressive and well-reasoned strategies for using the zoning code to encourage, or at least not discourage, the use of nonconforming properties for residential use. In doing so, they maintain or increase the supply of affordable housing available to the residents of their communities.



View of landscaped lawn and several new manufactured homes.

Regulating Manufactured Home Parks: Cost vs Improved Living Conditions

Manufactured housing is a source of affordable housing for many low- and moderate-income Americans. While wanting to respond to the demand for such housing, many local governments have established special regulations for manufactured housing/manufactured home parks to protect surrounding land uses. While many of these regulations improve conditions for those who live in the manufactured housing communities and protect surrounding land uses, they often increase the cost of this affordable housing resource. This article examines how a select group of communities implement regulations on issues such as setbacks and unit spacing, parking requirements, and utilities.

Minimum Development/Lot Sizes and Densities

Most communities set minimum sizes for manufactured housing developments. Communities with extremely large minimum park size requirements, however, limit the number of parcels available for development. Similarly, communities with low densities and large minimum lot sizes increase the amount of land required per unit. The following table provides some examples of various community minimums.


Minimum Manufactured Home Site

Maximum Manufactured Home Site

Maximum Density

Minimum Individual Lot Size

King County, Washington

3 acres

Not Stated

6 units per acre

Not Stated

Lancaster County, Virginia

20 acres

50 acres

3 units per acre

14,283 sf

Reading, Pennsylvania

5 acres

Not Stated

12 units per acre

2,500 sf

Santa Ana, California

Not Stated

Not Stated

10 units per acre

2,800 sf

St. Petersburg, Florida

15 acres

Not Stated

8 spaces per acre

4,000 sf

Setbacks and Unit Spacing

Local governments establish setbacks to provide residents with semi-private open space between units and for fire safety. Setbacks that are too large, however, take up valuable land and may increase the cost of providing this type of housing. King County’s minimum separation between manufactured homes is 10 feet. Santa Ana’s minimum distance between units is also 10 feet. In addition, the Santa Ana ordinance specifies a number of front, side, and rear yard setbacks. Lancaster County does not allow a manufactured home to be closer than 40 feet to any other home and no closer than 100 feet from any manufactured home park property line.


All local governments require park owners to create a vehicular transit system within the park. Private road system mandates have the potential to dramatically increase the cost of creating and maintaining a manufactured home park. Reading requires that internal streets be at least 20 feet wide and that cul-de-sac streets have a 40-foot right of way and paved surface of 24 feet. Santa Ana requires a 28-foot minimum paved surface. The Santa Ana ordinance goes on to say that such streets must be paved with 2 inches of asphalt concrete over 4 inches of aggregate base, and must have rolled curbs and gutters on both sides of the street. Lancaster County requires the right of way to be at least 50 feet, and the road to be at least 30 feet wide. The County further requires that driving surfaces have at least 2 inches of crushed stone base or be paved with asphalt or tar and gravel.

Parking Requirements

Parking is a requirement of almost all local ordinances. Depending on the number of spaces required and the design regulations, however, this requirement also has the potential to substantially add to the cost of producing a manufactured home lot. The communities below require either one or two spaces per unit and Santa Ana also requires the provision of guest parking. Several communities also have specific design requirements for the individual parking spaces.


Resident Parking

Guest Parking

Other Conditions

King County, Washington

1 per lot

None Stated

Must be located on or adjacent to manufactured home pad.

Lancaster County, Virginia

2 per unit

None Stated

Must be 8 feet wide, 20 feet long and paved.

Reading, Pennsylvania

2 per unit

None Stated


Santa Ana, California

2 per lot

1 for every 4 lots

Spaces must be within a specific distance of the manufactured home lot.

St. Petersburg, Florida

2 spaces per unit

None Stated



All local governments require owners of manufactured home parks to provide residents with public utilities, but some communities’ requirements are more extensive than others. Reading and Santa Ana require that all utilities be placed underground. In addition, Reading requires fire hydrants to be within 250 feet of each group of 12 manufactured houses.

Open Space

Many ordinances require a manufactured housing park developer to set aside a certain amount of land within the development for open space and recreation. As more land is required for park and open space, less land is available for income-producing lots. As seen below, some communities list the requirement as a strict percentage while others make the requirement as an amount of land per unit in the development.


Open Space Requirements

Additional Conditions

King County, Washington

260 sf per unit


Lancaster County, Virginia

20 percent of gross land area

Includes interiors of buildings designed for community use.

Reading, Pennsylvania

10 percent of site

Exclusive of rights-of-way.

Santa Ana, California

100 sf per unit


St. Petersburg, Florida

10 percent of site



Most local governments require owners to install some type of screening between manufactured home parks and surrounding land uses. The cost of providing these buffers depends on the type and amount of screening required. Authorities in Reading require screening along all sides abutting public streets or other properties. St. Petersburg, Santa Ana, and Lancaster County require a six-foot high barrier to be installed between the development and other property. Lancaster County requires a fence or hedge along the road frontage, while St. Petersburg requires the screening along the boundary with all adjoining properties. Lancaster County also requires that any hedge must reach six feet in height within two years of installation. Santa Ana’s requirement for a six-foot high barrier can be a wall or a screen with plant materials.


There are no definitive, across-the-board standards for what constitutes safe living conditions in manufactured housing developments, and some communities demand more from the developer/owner. The cost of these additional requirements is often passed on to those who look to manufactured home parks as a source of affordable housing.


Six San Diego city staff receiving an award

Award-Winning Program Streamlines Processing for Affordable Housing

San Diego recently received the San Diego Housing Federation’s "Outstanding Local Government Support" award for the City’s Affordable Housing Expedite Program. The Program, created after the City Council declared a city-wide housing state of emergency, streamlines the application process for affordable housing developments or developments that use sustainable energy technology.

In 2003, the San Diego City Council recognized that the City’s severe lack of affordable housing was having an adverse impact on many of San Diego’s residents, including those who work in the City’s health care, education, biotech, and tourism industries. As part of an overall effort to ease this problem, the City adopted an inclusionary housing ordinance, set-aside funds for new affordable housing, and created the Affordable/In-fill Housing and Sustainable Buildings Expedite Program.

Program Features

The Program consists of a number of features to increase private sector participation in creating affordable housing.

  • Mandatory Initial Reviews: A preliminary review, in which the applicant submits enough information so that city staff can initiate an environmental review early in the process and identify any potential fatal flaws in the proposal.
  • Easily Accessible Information: The entire program, including the mandatory preliminary review process, is explained in detail in Information Bulletin 538, and the mandatory preliminary review process is explained in Bulletin 513. In addition, San Diego provides Form 530, which contains a checklist developers can use when seeking to apply under the Program. All of this information is available online.
  • Committed Staff: According to Mike Westlake, Program Manager, Affordable/In-Fill Housing and Sustainable Buildings Expedite Program , the City Council is committed to the Program and ensures that staff is available to undertake these reviews in a timely manner. Anywhere from 12 to 15 City departments or agencies review each application . The staff in each department are knowledgeable, experienced, and customer service oriented. In addition, they work exclusively on the Program.
  • Fees: The Council authorized a $500 fee per unit to assist with staff costs for these new positions. Most developers consider the fee to be a minor inconvenience, especially in comparison to how much they save in carrying costs.
  • Program Priorities: Recognizing that the Program had the potential for overwhelming City staff resources, the Council established nine priorities for expedited processing. If at any time staff could not undertake timely reviews of all projects due to heavy workloads, they were authorized to reduce the number of priorities that would qualify for streamlined processing.


The Program is just over a year old, and in that time, the City has processed 23 projects comprising over 2,250 units. Of those units, over 2,170 are new affordable units and 80 are sustainable units. The City has approved discretionary permits for four projects, but none have yet applied for building permits as of July 2004. Westlake says that the processing time is twice as fast as under the old review process. While he admits that many of the projects would have been built without the Program, he believes that these much-needed housing resources will be on-line much quicker than before. He also states that several developers have indicated to him that they have added affordable units to the project mix in order to qualify for expedited processing.

Keys to Success

According to Westlake, there are a number of factors that have contributed to the success of the Program.

  • Meetings with Developers: One key to the program’s success is the meetings staff conduct with developers before plans and proposals are submitted to the City. In addition, the mandatory preliminary review meeting also serves as an important milestone in making the review process run smoothly.

  • Commitment by the Development Community: The $500 per unit fee has resulted in developers being more conscientious about submitting the appropriate material in a timely fashion.

  • City Staff Resources: Westlake attributes the City’s staff commitment as one of the keys to the success of the Program. Each of the City’s departments is represented by staff who genuinely wants the best projects possible for the City. Their commitment, coupled with the City’s commitment to have them work exclusively on these type of projects, is a major factor in the success of the Program.

  • City Communication: Staff comments are provided via email, so that each of the other departments can promptly be made aware of issues being raised by other departments. If the conflict cannot be resolved, it is immediately forwarded to the department head and is usually settled within two days.

Problems Remain

Ironically, the success of the Program could be its downfall. Because so many people are participating in the Program, in May 2004, staff had to curtail expedited reviews for all but the top three priorities listed in the original City Council Program. While City officials are working to secure additional staff for the program, there will inevitably be delays in processing requests for projects that are not deemed a priority.

The other concern with the Program is that it has not reduced NIMBYism or local opposition to affordable housing. While the Council remains committed to the Program and staff recommendations have garnered strong political support, neighborhood opposition remains and has the potential for slowing the review process.

More Information

For more information on this effort, visit our web link at


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