5.10 INTERNAL ACCESSORY DWELLING UNIT (IADU)
Unofficial copy. It may be out of date. Not legal or zoning advice. Zoning rules change, and only the city or county can say for sure what is allowed on a property. Confirm with the city or county planning department before you buy, sign or build.
The official Castle Valley code is at https://castlevalleyutah.gov/documents/ordinances.php.
Text pulled 2026-10-19 from this source.
Tables (like use tables) may not copy cleanly, so check any table against the official code.
Confirm anything here with Castle Valley planning before you rely on it.
One Internal Accessory Dwelling Unit is allowed within the building footprint of the Primary Dwelling. Each IADU shall require a permit with annual renewal, regardless of intended use. The IADU Permit is non-transferable and terminates upon sale of the property. New owners of a lot with a previously permitted IADU installed must apply for a new IADU Permit in their own name or decommission the IADU kitchen as provided for in this Section. Reinstating a previously decommissioned IADU shall require a new IADU Permit application.
5.10.1 Prohibitions A. Rental of the IADU is strictly prohibited if the owner of record of the Primary Dwelling is not a full-time resident within that Dwelling. B. IADUs, if rented, shall not be rented for a period of less than 30 days. C. IADUs are prohibited in detached structures. D. IADUs are prohibited within mobile homes.
5.10.2 Requirements A. IADU Application, on the form maintained by the Town. B. IADU Application fee. C. Verification that the property owner of record occupies the Primary Dwelling as their Primary Residence, as recognized by the Grand County Assessor in the public record Grand County Tax Information. D. An IADU or any space within the Dwelling that is modified as part of installation of an IADU must be compliant with current Building Codes, including but not limited to egress window requirements. This is to ensure the health and safety of all occupants of the building. E. Septic inspection and approval by Southeast Utah Health Department to ensure the septic system is adequate for the proposed use. F. Notice of the approved Internal Accessory Dwelling Unit, including Decommissioning Contract, signed by all of the property owners of the subject property and their signatures notarized, shall be recorded by the Town with the Grand County Recorder. The notice shall include: a description of the Primary Dwelling; a statement that the Primary Dwelling contains an Internal Accessory Dwelling Unit; and a statement that the Internal Accessory Dwelling Unit may only be used in accordance with the Town's land use regulations. Upon recording the notice, the Town shall deliver a copy of the notice to the owner of the IADU.
5.10.3 Internal Accessory Dwelling Unit Review Procedure The decision to approve or deny an IADU application is administrative. Within a reasonable amount of time after the applicant submits a complete IADU application, the Town shall approve the IADU application if it complies with the requirements of this Section 5.10 and all applicable building, health, and fire codes.
5.10.4 Renewal of Permits The owner of the property on which the IADU is located shall submit an IADU renewal application annually to ensure legal compliance. Within a reasonable amount of time after the applicant submits a complete IADU renewal application, the Town shall approve the IADU renewal application if it complies with the requirements of this Section 5.10. The Town may deny the IADU renewal application in the event the Town determined the owner violated Section 5.10.1(B) or if the owner has failed to cure any other violation of this Section 5.10 after notice pursuant to Section 5.10.6. In the event of denial of an IADU renewal application, the owner of the lot on which the IADU is located shall decommission the IADU pursuant to Section 5.10.5
5.10.5 Internal Accessory Dwelling Unit Decommissioning A. The IADU must be decommissioned no later than thirty (30) days after revocation or cancellation of the IADU Permit. B. Decommissioning the IADU shall consist of removal of some of the fixtures, facilities, or plumbing that are part of what defines a Dwelling Unit in this Land Use Ordinance, such as the removal of circuits, or abandonment of both ends of the circuit, and gas line stubs used for cooking facilities, all the way to the attic or the crawl space.
5.10.6 Enforcement of IADUs In the case of a suspected violation with respect to an IADU, the following procedures shall be followed. These procedures are in accordance with Section 10-9a-530, Utah Code Annotated 1953 (“Utah Code”).
A. Upon learning of a suspected violation, the Town shall provide a written notice of suspected violation (“Notice”). The Notice shall:
1. Be mailed to the owner of record and any other individual designated on the IADU permit to receive notice and posted at the property with the suspected violation;
2. Describe the specific violation; 3. Provide the owner of the IADU thirty (30) days from the day on which the Town issues
the Notice to file a written objection or to cure the violation, except in the case of a violation relating to an illegal Short-term Rental or for any issue relating to health or safety. In the case of a suspected violation relating to an illegal Short-term Rental or for any health or safety issue, the Notice shall specify that the suspected activity or use as an IADU must immediately cease and desist; 4. Provide the name and address of the Town office where the owner may file a written objection to the Notice; 5. State that if the owner fails to cure the violation within 30 days of the issuance of the Notice, or fails to cure the violation immediately if the Notice specifies a suspected violation relating to an illegal Short-term Rental or for any health or safety issue, the Town may hold a lien against the property in an amount up to $100 per day, for each day of the violation after the expiration of the 30-day cure period; 6. The Town shall record a copy of the Notice with the Grand County Recorder. B. If the owner cures the suspected violation to the satisfaction of the Town within the 30-day cure period, or immediately in the case of a suspected violation relating to an illegal Short-term Rental or for any health or safety issue, the Town will not hold a lien against the property nor impose any fees or fines upon the owner with respect to the suspected violation specified in the Notice.
5.9 CONVERSION OF EXISTING DWELLING TO AN ACCESSORY BUILDING · 6.1 NONCOMPLYING BUILDINGS