1. Accessory Dwellings Offer Many Benefits

By: Tom Hiznay, AICP, Senior Planner, Planning/Zoning Division

Like other jurisdictions in Florida, Hillsborough County’s development regulations allow only one dwelling unit on lots that are zoned for single-family homes. However, unlike most other jurisdictions, our regulations provide an exception for “accessory dwellings.” Commonly known by several names, including granny flats, mother-in-law suites and garage apartments, an accessory dwelling is a small, independent living unit located on the same lot with a detached single-family home.

According to a 2008 report prepared for the Hillsborough County Affordable Housing Advisory Board, of 290 local governments in the state surveyed by the Florida Department of Community Affairs, only 46 had provisions for accessory dwellings. “As presently written, Hillsborough’s land development code does not appear to impose any major impediments to the use of accessory dwellings,” the report stated. “It is more receptive to accessory dwellings than most land use codes in the State of Florida.”

Benefits
Accessory dwellings offer numerous benefits to property owners and the community at large. They maximize the utilization of existing public infrastructure and transit services; help limit residential sprawl and rezonings of open land; provide affordable housing options within the stable social context of established neighborhoods; generate additional income for homeowners; increase property values and tax revenues; and allow residential care alternatives for family members such as elderly parents. In view of these benefits, an increasing number of communities across the nation are actively promoting the development of accessory dwellings by offering incentives to homeowners such as architectural design assistance, streamlined permitting and financial subsidies.

“Communities find that allowing accessory dwelling units [ADUs] is advantageous in many ways,” concludes a 2008 report by HUD’s Office of Policy Development and Research. “In addition to providing practical housing options for the elderly, disabled, empty nesters and young workers, ADUs can provide additional rental income for homeowners … They are an inexpensive way for municipalities to increase their housing supply, while also increasing their property tax base.”

Requirements
In Hillsborough County, accessory dwellings are allowed in most of the zoning districts which permit single-family homes, subject to the requirements found in Section 6.11.02 of the Land Development Code. Compliance with these requirements is reviewed by Building Services Division staff during the construction permitting process, thereby eliminating the need for a separate zoning review.

The approval requirements for accessory dwellings are straightforward, but include two important restrictions. First, the primary dwelling on the parcel must be owner occupied. And second, the accessory dwelling cannot, in most cases, have more than 900 square feet of living space. This space includes all areas that are utilized for living, sleeping, eating, cooking, bathing, washing, sanitation, laundry and storage purposes, excluding garages and attics.  The space is measured from the outside faces of the exterior walls.

It’s important to note that NO exceptions are allowed to the owner occupancy requirement, while variances to increase the maximum size of an accessory dwelling may be requested ONLY when the primary dwelling on the parcel has more than 3,600 square feet of living space, and the parcel is at least 14,520 square feet in size. In such cases, a variance to increase the living space in the accessory dwelling to 1,200 square feet or 25 percent of the living space in the primary dwelling, whichever is less, may be requested.  This process requires a noticed public hearing and approval at the discretion of the hearing officer. Consequently, any homeowner wishing to build an accessory dwelling should make sure his design professional is aware of the 900-square-foot living space restriction to avoid the need for plan revisions or, when allowed, a variance.

Accessory dwellings may be attached to the primary dwelling on the parcel or detached. In either case, the accessory dwelling must have its own bathroom and kitchen facilities. Quarters which lack a bathroom or kitchen cannot be used as an accessory dwelling.

For More Information
The accessory dwelling regulations contained in Section 6.11.02 of the Land Development Code may be reviewed online.  You also can visit the Planning and Growth Management Department’s website for more information. PGM staff is available to answer questions by calling (813) 272-5920 or visiting the 20th floor of County Center, 601 E. Kennedy Blvd., downtown Tampa.