The simple answer
Site planning should happen before the detached structure design is treated as final. The building location needs to work with setbacks, lot coverage, easements, utilities, driveway access, existing structures, and the local review path.
Helpful information to gather first
Property address and jurisdiction
Survey, site plan, assessor sketch, or recorded plat if available
Preferred structure location and rough building size
Known easements, septic location, washes, floodplain, or drainage constraints
Desired driveway path, garage door direction, and vehicle access needs
HOA or subdivision requirements if they apply
Site items that commonly affect detached structures
Local requirements vary, but the same site categories tend to drive early planning decisions across Phoenix Metro communities and surrounding Arizona areas.
Setbacks
Setbacks define how close a detached structure can be to property lines or other features. Side, rear, front, and separation requirements can vary by jurisdiction, zoning, height, and use.
Existing structures
The main home, patios, pools, walls, sheds, septic equipment, and previous additions can all affect where a new garage, shop, or casita can reasonably fit.
Easements and site constraints
Utility easements, drainage easements, washes, floodplain areas, septic setbacks, and access limitations can reduce the usable building area.
Driveway and access
RV garages, shops, and detached garages need practical access. Door placement, turning space, slope, gates, and existing driveways should be checked early.
Common planning mistakes
Many detached-structure redesigns happen because the desired building was planned before the property constraints were understood. A little site information early can save a lot of rework later.
- Designing the building footprint before checking setbacks and easements
- Forgetting about vehicle access, turning space, gates, and driveway alignment
- Ignoring septic, drainage, floodplain, or utility constraints on larger lots
- Assuming the same setback rule applies in Phoenix, Mesa, Queen Creek, Scottsdale, and Maricopa County
- Treating a casita, RV garage, shop, and simple storage building as the same review problem
Jurisdiction matters
Phoenix, Mesa, Scottsdale, Gilbert, Chandler, Queen Creek, and Maricopa County may use different zoning, building, and submittal processes. The plan set should match the property location.
Access is part of design
Door direction, driveway alignment, RV turning radius, gates, and existing hardscape can affect whether the detached structure works in real life.
Related detached structure planning
If the project is an RV garage, see RV garage plans in Arizona. For shops and workshops, read detached shop plans in Arizona. For a full overview, start with detached structure plan basics.
Need help planning a detached structure site?
Residential Design can help organize site-aware plans for detached garages, RV garages, shops, casitas, and accessory structures in the Phoenix Metro area and surrounding Arizona communities.