Belmont, population 26,941 (2019), is located on the San Francisco Peninsula, 25 miles southeast of downtown San Francisco. Portions of the City contain undeveloped subdivisions approved more than 50 years ago for land with steep, and in some cases unstable, slopes. In 1988, the City adopted new zoning provisions designed to encourage the preservation of the steepest and most unstable slopes through a combination of density restrictions, development requirements, transfer of floor area, and transfer of development rights.

In creating the Hillside Residential and Open Space (HRO) zoning district, Belmont recognized the need to minimize the destruction of unique terrain features which are important to the character of the City. Belmont also acknowledged that there are geologic problems, soils hazards, and steep slopes that generate public safety concerns. To deal with these issues, Belmont concluded that hillside development should preserve the natural terrain and provide a density compatible with slope limitations.

The HRO-2 zone applies to land that has already been subdivided. In this zone, lots 40,000 sf or larger are limited to a maximum floor area of 3,500 sf. Lots smaller than 40,000 sf can be as large as 1,200 on land with an average slope of 10 percent or less. The maximum floor area decreases as the lot slope increases but allows a floor area of 900 sf on lots 45 degrees or steeper. The allowable floor area includes the entire area under the roof, including the garage; consequently, a 1,200 square-foot dwelling might contain a 400 square foot garage and only 800 square feet of living area.

The amount of floor area that can be transferred to a receiving site is the greater of either 1,200 square feet of floor area or the amount of floor area which could actually be built on the sending site. However, the maximum floor area allowed on any site, even with transfers, is 3,500 square feet. These density limitations encourage the owners of steeply-sloped lots to transfer their development rights. These owners are further motivated to consider transfers by Belmont’s requirement for a geotechnical study of every proposed development site with potential slope stability problems.

Originally transfers of development rights from sending sites had to be made to receiving sites along the same roadway and within the same statistical subarea of Belmont’s San Juan Hills Area Plan. A 2018 code amendment changed that provision to allow transfers between any properties in the HRO-2 zone. In approving a conditional use permit for transferred floor area, the planning commission must make six findings. For example, the commission must find that the proposed transfer will result in a better pattern of development from the standpoint of reduced grading, fewer street/utility extensions, and improved building site locations. The Commission must also find that the sending site will be protected from future development by a conservation easement and that management of the sending site be adequately provided for.

In addition to the transfer of floor area discussed above, the owners of property in the HRO-2 Zoning District can transfer units between properties in the HRO-2 zone via a conditional use permit approved by the Planning Commission. The receiving site must be at least 20,000 square feet in area; new lots created through the transfer process must be at least 10,000 square feet and need not comply with the regular minimum lot size standards of the HRO-2 Zone. One additional dwelling unit is allowed on a receiving site for three sending lots which have been permanently preserved through a conservation easement. In approving a density transfer, the Planning Commission must make findings that are similar to those required for the granting of a floor area transfer.

The Belmont TDR program contains some of the factors often found in successful programs. The floor area restrictions give property owners an incentive to transfer floor area rather than build a smaller home on site. Those sending site owners who understand the program also realize that transferring density can be more cost-effective than building the necessary infrastructure on problematic sites.

Between 1988, when the program was adopted, and 1995, eleven transfers were approved. A single development was involved in ten of the eleven transfers. In this project, the road drawn in the original subdivision map traversed a landslide area. Lots from the original subdivision which were shown in the landslide area were permanently preserved by deed restriction. The floor area from these lots was used to increase the floor area of homes on other lots on the same street. This transfer was approved in 1990, but construction of the ten homes did not start until 1995.

In the remaining case, a property owner was granted approval to transfer 1,200 square feet of floor area from a sending parcel in order to build a 2,400 square-foot home on a receiving site. Without this transfer, the receiving site would only have been allowed 1,200 square feet of total floor area. The residence on the receiving site was completed in 1995. The sending site was permanently preserved by a conservation easement.

Between 1995 and 2009, Belmont approved transfers that resulted in the consolidation of eight lots into four lots. One acre was preserved in the process. According to Senior Planner Bill Chopyk, the program’s success is due to the fact that the owners of lots in antiquated subdivisions can gain some economic return from property which would be difficult or impossible to develop under current subdivision standards.

In a 1998 letter, Daniel Vanderpriem, Director of Planning and Community Development, reported that the TDR program was working as expected. Rising real estate prices in the San Francisco Bay area make it more profitable to develop marginal lots, like those in the Belmont sending area, because the high cost of grading and access represents an increasingly smaller percentage of overall costs. However, the rate at which these marginal lots become feasible to develop has been slow enough that TDR remains a viable alternative to on-site development.