Zoning codes serve to control the amount of building construction in order to satisfy acceptable community standards related to residential densities and living conditions. One such requirement is the maximum number of units that can be built on a property. Density varies depending upon the residential zone in which it is located, for example, R-1 (Single Family), R-2 (Medium Density) or R-3 (High Density) and/or the property's land area.
R-1 Single Family
The R-1 zone is the basic building block of a community. The name itself, single family residential, expresses the nature to which the type of construction that is allowed, one single family house, unless the property is large enough to subdivide into more lots that satisfy the minimum area requirement of 6,000 square feet. As you further discuss the requirement with a planner, you will be advised that there may be a maximum size (floor area) of the house that is permitted which is compared to the size of the lot. This is referred to as floor area ratio.
R-2 Medium Density
For multiple family zoned properties, R-2 and R-3, density calculations vary to a degree and are based upon the lot frontage and lot area of the property. The basic rule is that the greater the lot frontage and lot area, the more number of dwelling units that could possibly be built.
R-3 High Density
In the R-3 zone, a lot with a frontage of 50 feet or greater and which has a lot are of 7,000 square feet, the ratio is one unit per 3,000 square feet of land area. Accordingly, a 10,000 square foot lot in the R-3 zone has the potential to be developed with more units.