ADU Eligibility Checker

Can You Build an ADU on Your Property?

Check your eligibility in seconds. Our tool evaluates state laws, zoning requirements, lot size, and HOA rules to tell you if an ADU is possible on your property.

ADU Eligibility Checker

Find out if you can build an ADU on your property. Enter your details below for an instant assessment based on state and local regulations.

Property Details

6,000 sq ft
1,000 sq ft50,000 sq ft

Eligibility Assessment

California · 6,000 sq ft lot · Single-Family zoning

Likely Eligible

Your property appears to meet state-level ADU requirements

Confidence:
medium — state-level data

Allowed ADU Types

Detached ADU
Attached ADU
Garage Conversion
Junior ADU (JADU)

Maximum ADU size: 1,200 sq ft

Key Rules & Restrictions

Maximum ADU size: 1,200 sq ft (or 50% of lot, whichever is less)

California ADU Legislation

Key legislation: AB 976 (2024), SB 543 (2025)

  • •AB 976 eliminated owner-occupancy for ALL ADU types effective January 1, 2024
  • •SB 543 (2025) includes deemed-approved mechanism for delayed permits
  • •AB 462 provides 60-day deemed-approved for coastal zone ADUs (effective Oct 10, 2025)
  • •HOAs cannot restrict ADU construction under state law
  • •CalHFA ADU Grant ($40K) is CLOSED — fully allocated December 2023
  • •1 ADU + 1 JADU allowed per single-family lot; multi-family allows up to 2 detached ADUs

Recommended Next Steps

1Verify eligibility with your local planning department — state rules are a floor, not a ceiling
2Get a preliminary site assessment from a licensed contractor
3Use our Cost Estimator to budget your project
4Explore financing options with our Financing Calculator

Important: This is general guidance based on state law. Local ordinances, overlay zones, and specific property conditions may affect eligibility. Always verify with your local planning department before starting any ADU project.

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Can You Build an ADU on Your Property?

Accessory Dwelling Units (ADUs) have become one of the most popular ways to add living space, generate rental income, and increase property value. But before you start planning, you need to know whether your property qualifies. ADU eligibility depends on a combination of state law, local zoning codes, lot characteristics, and homeowner association rules.

State-Level ADU Laws

A growing number of states have passed laws requiring cities to allow ADUs. California leads the way with comprehensive legislation including AB 976 (2024), which eliminated owner-occupancy requirements for all ADU types. Washington's HB 1337 (2023) requires cities to allow at least two ADUs per lot and prohibits HOA restrictions. Oregon's SB 1051 (2017) and HB 2001 (2019) mandate ADU allowances with no owner-occupancy or parking requirements. States without statewide mandates — including Texas, Florida, Colorado, Arizona, and Nevada — leave ADU regulation entirely to local jurisdictions, creating a patchwork of rules that varies city by city.

Zoning and Lot Requirements

Even in states with ADU mandates, your specific zoning designation matters. Most ADU-friendly states require cities to allow ADUs in single-family residential zones (R-1, RS, SF). Multi-family and mixed-use zones may have different rules. Lot size minimums vary — California has effectively eliminated minimum lot sizes for ADUs, while other jurisdictions may require 5,000–6,000 square feet. Maximum ADU size is typically capped at 800–1,200 square feet or a percentage of the primary dwelling, whichever is less.

HOA Restrictions

Homeowner associations have historically been a major barrier to ADU construction. However, several states have passed laws overriding HOA restrictions. California and Washington explicitly prohibit HOAs from blocking ADUs. Oregon's HB 2138 (2025) will retroactively void HOA ADU restrictions effective January 1, 2027. In states without such protections, your HOA's CC&Rs may effectively prevent ADU construction regardless of local zoning.

Types of ADUs You Can Build

ADUs come in several forms, each with different regulatory treatment. Detached ADUs are standalone structures in your backyard. Attached ADUs share a wall with your primary home. Garage conversions transform existing structures into living space — often with fewer permitting hurdles. Junior ADUs (JADUs), available primarily in California, are small units (under 500 sq ft) created within the existing footprint of a home. Basement conversions are allowed in many jurisdictions where basements are common. The type of ADU you can build depends on your property features and local regulations.

Disclaimer: This eligibility checker provides general guidance based on state-level legislation. Local ordinances, overlay zones, historic district designations, and specific property conditions may impose additional requirements or restrictions. Always verify with your local planning department before beginning any ADU project.

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Frequently Asked Questions

Can I build an ADU in my backyard?
It depends on your state and local zoning. States like California, Washington, and Oregon have statewide mandates requiring cities to allow ADUs on single-family lots. In states without mandates, eligibility depends on your city's zoning code. Use the eligibility checker above to get an instant assessment for your property.
Can my HOA prevent me from building an ADU?
In California and Washington, state law overrides HOA restrictions — your HOA cannot block an ADU. Oregon's HB 2138 (2025) will void HOA ADU restrictions starting January 1, 2027. In most other states, HOAs can still restrict or prohibit ADUs through CC&Rs. Check both state law and your HOA documents.
Do I need to live on the property to build an ADU?
Not in every state. California eliminated owner-occupancy for all ADU types with AB 976 (2024). Oregon dropped the requirement with HB 2001 (2019). Washington also does not require it. Massachusetts requires the owner to occupy either the primary dwelling or the ADU. Rules vary — check your state and local requirements.
How many ADUs can I build on my property?
California allows 1 ADU plus 1 JADU on single-family lots, and up to 2 detached ADUs on multi-family properties. Washington requires cities to allow at least 2 ADUs per lot. Oregon mandates 1 statewide, though Portland allows 2. States without mandates leave the limit to local jurisdictions.
What is the maximum size for an ADU?
It varies by location. California caps detached ADUs at 1,200 sq ft. Oregon typically allows up to 900 sq ft. Washington allows up to 1,000 sq ft in many areas. Most jurisdictions also cap ADU size at a percentage of the lot or primary dwelling (commonly 50%). JADUs are limited to about 500 sq ft.