R-3 Zoning in Phoenix, AZ

4 Replies

Hello! I am a little embarrassed to ask this but after researching R-3 Zoning, I have a few questions:


     - I have a lot, nearly 6k square feet, in Phoenix AZ and it is zoned R-3

     - It currently has two duplexes on it for a total of four units

     - At least one of the units is an addition

     - I am uncertain as to the permits, however I did purchase it this way and there were no questions or issues in inspection or appraisal

     - I am considering adding another unit or two, or at the very least expanding a unit to add another bedroom.


     - In reading the coding, I am not sure where I land (Conventional or Planned Residential Development - I am assuming conventional but unsure of the distinction)

     - I am a little confused as to whether the rules for dwelling unit density are specific to number of units or number of structures

Any feedback would be so very appreciated!

@Jessica Jay-Maleski R-3 is three dwelling units per acre. Best thing to do is go to your city or county zoning dept for explanation and allowable uses. Every jurisdiction has their own zoning rules with their own nuances, exceptions and loopholes.

As Greg mentioned the zoning stipulates the number of units / acre, but I believe it is more than 3 in Phoenix.   I see that you are a realtor so if you check Monsoon, it will tell you the 'city zone'.  We're actually building on an R-3 lot right now, 9,250 sf, and we were capped at 3 so it was more like 12 units / acre.  I'm thinking that you are maxed out already and may have some units that were added without permits.  Sometimes it's easiest to just go downtown to the building department and ask for residential site planning.  They can tell you exactly what you can do.  Many times the ability to build more units is restricted more by parking requirements than zoning.  You can also check historical permits on the 3rd floor.  Good luck - 

@Jessica Jay-Maleski  Actually R-3 zoning varries vastly from city to city. In  the city of Phoenix Az there are different R-3 types which range from 5 units per gross acre to 17.4 units/gross acre. There are also lot coverage ratios which will effect the number of units allowed. Try a quick search on google. 

Hopefully this helps!

@Jessica Jay-Maleski I was a City Planner for the Town of Gilbert for 5 years. You need to check what the minimum lot area per unit requirement is in the R-3 zone. For example, if the minimum lot area per unit in the R-3 zone is 2,000 SF, then an 8,000 SF lot could allow for 4 units. Make sure you know what your net lot area is vice the gross lot area. For example, say the lot is 6,000 SF, but the Engineering Dept requires a 20-foot right-of-way dedication for new curb, gutter and sidewalk improvements across the street frontage of your lot. Subtracting that area gives you your net lot area.

You also need to check what the minimum unit sizes are based on the number of bedrooms in each unit. Each city has its own requirements on the minimum interior floor area of a 1 bedroom, 2 bedroom, etc.