The simple answer
Casita plans usually need to show the building location, room layout, exterior form, utilities, construction notes, and how the space will be used. Because casitas often include plumbing, HVAC, and habitable rooms, they typically need more detail than a detached garage.
Helpful information to gather first
Property address and jurisdiction
Whether the casita is detached, attached, new, or converted from an existing structure
Intended use, such as guest space, family living, office, studio, or rental-related use
Bathroom, kitchenette, laundry, HVAC, and utility expectations
Approximate size, number of rooms, and connection to outdoor areas
Any HOA, septic, floodplain, utility, access, or zoning constraints you already know about
What casita plans usually need to show
A casita is not just a small floor plan. The plan set should explain the living-space function, site relationship, utilities, envelope, and review items that help the city, town, or county understand the proposal.
Use and layout
Casita plans should clarify the room layout, sleeping areas, bathroom or kitchenette locations, doors, windows, and how the space will function in relation to the main home.
Site planning
Detached casitas need careful placement around setbacks, existing structures, utility routes, drainage, access, patios, privacy, and outdoor circulation.
Utilities and systems
Plumbing, electrical, mechanical, insulation, ventilation, and water-heater decisions can affect the permit drawings and coordination needed before submittal.
Jurisdiction review
Phoenix, Scottsdale, Mesa, Gilbert, Chandler, Queen Creek, and Maricopa County may review guest houses and accessory living spaces through different local requirements.
Common review questions
The right path depends on the property, jurisdiction, and intended use. A guest room, pool house, detached office, and independent living space may raise different questions.
- Whether the casita is allowed for the intended use on the property
- Setbacks, lot coverage, height, and separation from other structures
- Parking, access, utility connections, and service locations
- Kitchenette, bathroom, laundry, HVAC, and independent utility questions
- Energy, structural, plumbing, mechanical, and electrical coordination
Placement drives the design
Privacy, views, patios, utility runs, setbacks, and access often shape a casita as much as the room layout. The site should be understood before the plan is locked in.
Utilities change the scope
A bathroom, kitchenette, laundry, or separate HVAC system can add coordination. These decisions should be discussed before permit drawings begin.
Related detached structure planning
For a broader overview of garages, shops, casitas, and accessory structures, read what detached structure plans usually need to show. If placement is the main question, start with detached structure setbacks and site planning basics.
Planning a casita or guest house?
Residential Design can help prepare residential plan sets for casitas, guest houses, and detached accessory living spaces in the Phoenix Metro area and surrounding Arizona communities.