Sign up for our newsletter.

Atlanta TDR Margaret Mitchell House 9490 WestLampeter San-Diego-Receiving-Zone South-Street-Seaport-154 San-Francisco-Actual-Certified-Sending-Site-635-Pine jefferson West_Hempfield HistoricDowntown

Belmont, California

Belmont, population 25,835 (2010), 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 and transfer of development rights. The first section of this profile is taken from the 2003 book Beyond Takings and Givings. That book was based on a version of the Hillside Residential Ordinance as modified in 1991. The final section offers an update of changes that occurred between then and 2011.

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.

In the HRO-1 zone, density can be limited in terms of dwelling units per acre because land in this zone has not yet been subdivided. The HRO-1 zone decreases residential density as the slope increases. For lots smaller than one acre in size, the number of dwellings allowed per acre ranges from a maximum of 4.2 units per acre on slopes of ten percent or less to a minimum of 0.3 units per acre on slopes greater than 45 percent.

The HRO-2 zone applies to land that has already been subdivided. In this zone, lot sizes have already been determined but Belmont controls density by limiting the size of dwellings based on the average slope of the lot. For example, when the average slope of a lot is ten percent or less, for each square foot of lot area, 0.35 square feet of residential floor area is allowed, or floor area ratio (FAR) 0.35. When the average lot slope exceeds 45 percent, the density limit is reduced to FAR 0.26. As a result, an extremely steep 6,000 square foot lot would be limited to 1,560 square feet of floor area. Any legal lot is allowed to have at least a 1,200 square foot dwelling regardless of slope and lot size limitations. However, the allowable floor area includes the entire area under 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.

Transfers of development rights from sending sites must be made to receiving sites along the same roadway and within the same statistical subarea of Belmont’s San Juan Hills Area Plan. Transfers of development rights must be approved by the Zoning Administrator through an administrative conditional use permit. However projects with a floor area ratio exceeding 0.5 are subject to a public hearing by the Planning Commission.

In approving a conditional use permit for transferring floor area, the Planning Commission must make six findings. In one finding, the proposed transfer must result in a better pattern of development from the standpoint of reduced grading, fewer street/utility extensions and improved building site locations. In another finding, the Commission must verify that the sending site will be protected from future development by a conservation easement and maintained either through merger with a contiguous property, fee ownership by a conservation organization, fee ownership by the owners of the receiving site or some other satisfactory mechanism.

In addition to the transfer of floor area discussed above, the owners of property in the HRO-2 Zoning District can transfer units from one area to another along the same roadway and within the same statistical subarea 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 which 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. In addition, the owners of receiving sites are interested in extra density and, so far, TDR has been the only mechanism used to obtain this extra density. Finally, the transfer of smaller amounts of floor area can be approved administratively. On the other hand, the density transfer component requires the preservation of three sending lots in order to allow one more receiving lot; this negative transfer ratio is the lowest of any of the programs studied to date.

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.

Since 1995, Belmont has 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.

Current 2011 Ordinance

The profile above was based on a version of the ordinance as amended in 1991. Belmont adopted further amendments in 2001, 2002, 2003 and 2005 which are arranged below in the order that they appear in the ordinance as it existed in August 2011.

  • 4.73(o) adds secondary dwelling units as a conditionally permitted use.
  • 4.7.9 (Table 1) features major changes in the allowable density on hillside land. Previously, land with slopes of 10 percent or less could achieve a density of 4.356 dwellings per acre. The 2002 amendment changed that to 1.452 dwellings per acre. The number of dwellings allowed per acre decreases as the slope increases and now tops out at 0.108 dwellings per acre when slope is 45 degrees or higher, substantially less than the 0.325 dwellings per acre previously allowed.
  • 4.7.11(b) (Table 2) regulates the floor area ratio in the HRO-2 zone, the zone that pertains to subdivided land. Prior to the 2003 amendment, minimum floor area was 1,200 square feet regardless of the slope of the lot. Now, the minimum allowed floor area is 1,200 square feet for lots with slopes of 30 percent or less and then decreases as slope increases to a minimum floor area of 900 square feet when lot slope is 45 percent or more.
  • 4.7.11(c) now allows vacant non-conforming lots a minimum floor area that is the larger of either the minimum floor area or the allowable floor area ratio depicted in Table 2.
  • 4.7.11(g)(1) now requires that the applicant be informed of the right to appeal the Zoning Administrator’s decision.
  • 4.7.13 now prohibits the use of Section 4.2.10 to approve exceptions to the floor area standards.