A basement ADU (Accessory Dwelling Unit) is a fully independent living space built within the lower level of a single-family home. Designed to function as a standalone residence, it typically includes its own kitchen, bathroom, sleeping area, and a private entrance. This smart use of existing square footage allows homeowners to expand their usable living space without altering the exterior footprint of the property.
A basement ADU (Accessory Dwelling Unit) is one of the smartest ways to add livable space and value to your California property. Whether you’re looking to generate passive income, create housing for family, or simply make better use of your existing home, converting your basement into an ADU is a practical and high-impact solution.
A basement ADU conversion is an increasingly popular choice for California homeowners looking to:
1.Generate rental income through long-term or short-term leases.
2.Provide housing for family—ideal for aging parents or adult children.
3.Increase home value with a legally permitted second unit.
4.Avoid major additions by utilizing existing square footage.
5.Comply with California ADU laws, which often favor internal conversions.
The cost of a basement ADU in California typically ranges from $60,000 to $150,000, depending on the basement’s current condition, the size of the unit, and the level of finishes.
Key factors that affect pricing:
1.Ceiling height and basement access.
2.Foundation and waterproofing requirements.
3.Kitchen and bathroom installation.
4.Plumbing, electrical, and HVAC upgrades.
5.Permitting and design costs.
Typically 3 to 6 months, depending on permitting and construction scope.
Choosing Ataman Studio means working with a team that combines design excellence, and client-focused service.
Yes, most California cities allow rentals—but some require owner-occupancy. We’ll guide you through local rules.
In most cases, yes. You save on foundation, roofing, and exterior walls.
Yes, proper permits are required. We handle all the paperwork and approvals.
