San Tan Valley casitas: town rules or Pinal County?

Step one: town or county?

San Tan Valley is now an incorporated town. Since July 1, 2026, properties inside town limits follow the Town of San Tan Valley zoning ordinance. Properties outside town limits follow Pinal County rules. Check your address first. (Town Code)

Ask whether your building permit goes to the town or to Pinal County, since the town is still setting up its services.

Inside town limits

The town's zoning ordinance is new. We have not confirmed its casita size, setback or height numbers, or its rules for shops, so ask the town before you design. We will add numbers here once we confirm them.

Outside town limits: Pinal County

A 2025 law (HB 2928, ARS 11-810.01) applies the same basic ADU rules to unincorporated county land, with no population minimum. Counties had until Jan. 1, 2026 to adopt rules. Pinal County adopted its ADU rules in December 2025 (Board minutes, Dec. 10, 2025).

• Under these laws, cities and counties cannot require more than a 5-foot side or rear setback for an ADU, cannot require extra parking for it, and cannot require it to match your home's design.
• Cities and counties must allow an ADU of at least 75% of the home's interior living area or 1,000 square feet, whichever is less. Some allow larger ADUs with extra conditions.
• You can rent an ADU long-term (90 days or more, or month to month). The city cannot require the tenant to be a relative or employee.

For a shop or RV garage, ask the county for its accessory building height and setback limits. We have not confirmed them.

Shops and RV garages

Bigger lots and fewer HOAs make parts of the San Tan Valley area appealing for shops. Town and county shop limits are not confirmed yet, so ask before you buy plans.

• A 14-foot RV door usually means 16 to 18 foot walls and an 18 to 22 foot roof peak.
• The 5-foot ADU setback covers the living unit, not a shop. See shops and RV garages.

More on costs: RV garage cost by size and RV garage with a casita.

Cost notes

Our 2026 rates: $195 to $265 per sq ft for a casita of 500 sq ft and up, and $95 to $135 per sq ft for a stucco shop. Long utility runs are common on larger lots. They add $4,500 to $8,000.

How to choose a casita builder in San Tan Valley

We do not rank or recommend builders. Use this checklist with any contractor you talk to.

1. Check the ROC license. Search the contractor on the Arizona Registrar of Contractors site. Make sure the license is active and covers residential work, and that the name matches the bid.
2. Ask for proof of insurance. Get a certificate for liability insurance, and for workers' comp if they have employees.
3. Get a written bid. It should list plans, permits, site work, utility runs, the slab, AC and finishes, plus any allowances. Compare it line by line with our line items.
4. The contractor should pull the permits. Ask who pulls them. If you are asked to pull them yourself, ask why.
5. Tie payments to finished work. Avoid paying most of the price up front.
6. Ask for local projects. Ask whether your permit goes to the Town of San Tan Valley or Pinal County, and whether they have pulled permits with both.

Areas we cover

ZIPs 85140 and 85143, inside and outside town limits. Parts of 85140 are in Queen Creek; see the Queen Creek page.