All residential zones include some limit on density. There is a lot of confusion concerning the use of terms "dwelling unit", "density unit", "lot", "parcel", "tract", and the like. Also, the distinction between "gross" and "net" in determining some limits. There needs to be a complete cleanup of the BCZR to clarify these terms and then to ensure that all uses are consistent.
Various parts of the BCZR give the following for residential density (this is not complete or guaranteed to be accurate):
- DR1 1 dwelling units/acre
- DR2 2 dwelling units/acre
- DR3.5 3.5 dwelling units/acre
- DR5.5 5.5 dwelling units/acre
- DR10.5 10.5 dwelling units/acre
- DR16 "16 density" (the word "unit" is obviously missing here)
- RC2 minimum lot 1a, large subdivision no more than 1 lot per 50a
- RC3 may be less than 1a in cluster, but no more than .3 dwellings per acre
- RC4 minimum lot 3a, but also says 1a less than 6a may not be subdivided, max .2 lots per acre
- RC5 minimum lot 1.5a, max density .5 dwelling per acre
- RC6 completely ambiguous
- RC7 minimum lot 25a, .04 lot per acre (but then says "lat must not be less than 1a")
- RC8 minimum lot 10a (The entries in the table in 1A09.7 are obviously in error. They make no sense.) For greater than 50a, .02 lots per acre. But also says "not less than 3a".
- RC20 minimum lot 20a (with exceptions for intrafamily transfer)
- RC50 minimum lot 20a if parcel up to 100a is subdivided, 50a if parcel greater than 100a is subdivided (with exceptions) - So, if you have 100.0a, it can be divided into 5 lots. If 100.1a, only 2 lots. Makes a lot of sense!
These are too complicated to understand, and often make no sense.