ADU Regulations in Mountain House, California (2026)

Regulations at a glance

Local rules & notes

Animal-Keeping Proximity Waiver: ADUs and JADUs are exempt from the standard 35-foot minimum distance requirement from animal-keeping structures (stables, corrals, etc.). Front Yard Encroachment Allowance: An ADU of 800 square feet or less may encroach into the required front yard setback if there is no other location on the property where it could be built. Historic Resource Objective Standards: Introduces specific objective architectural standards for ADUs on historic properties to ensure preservation while maintaining ministerial (fast-track) approval.

For the official ordinance and latest updates, check your city or county planning department.

Frequently asked questions about ADU regulations in Mountain House

• What is the maximum ADU size in Mountain House, California?

  In Mountain House, the maximum ADU size is typically 1200 square feet, depending on whether the unit is attached or detached. California state law allows up to 1,200 sq ft for detached ADUs and 800 sq ft for attached in many jurisdictions; Mountain House may follow state defaults or have local limits. Verify with Mountain House planning for your specific lot.

• What are the setback requirements for ADUs in Mountain House?

  In Mountain House, typical setback requirements are 4 feet from the side property line and 4 feet from the rear. These may be reduced to 4 feet under California Government Code § 65852.2 where applicable. Check with Mountain House planning for overlay zones or design standards that could affect your site.

• What is the maximum height for an ADU in Mountain House?

  In Mountain House, the maximum height for an ADU is generally 25 feet. State law often allows up to 16 feet for detached ADUs and up to 25 feet when within 4 feet of the property line in some cases. Confirm with Mountain House or county planning for your zone.

• Is ADU approval ministerial in Mountain House?

  In Mountain House, ADU approval is typically Ministerial (by-right) per Gov Code §65852.2. Ministerial (by-right) review means the city must approve qualifying applications without discretionary review, per California Gov Code § 65852.2. Your project must still meet objective standards; Mountain House planning can confirm the exact process.

• Are there parking requirements for ADUs in Mountain House?

  In Mountain House, parking for ADUs is generally false. California law often waives parking for ADUs within a half-mile of transit or in certain historic districts. Check with Mountain House planning for your address.