Hillsboro ADU Regulations & Building Guide

Hillsboro is a vibrant community located in Oregon with a population of approximately 106,612. As demand for housing continues to grow, accessory dwelling units (ADUs) have become an increasingly popular solution for homeowners looking to add living space, generate rental income, or house family members.

GatherADU provides comprehensive ADU services to Hillsboro residents, including custom design, permit assistance, and full construction management. Our team understands local building codes and zoning regulations to ensure your project proceeds smoothly.

Oregon State ADU Laws

Oregon has embraced ADU-friendly legislation to address housing needs. State law requires cities to allow ADUs on single-family residential lots.

Key Oregon ADU Regulations:

• Size Limits: Typically up to 800-900 sq ft, depending on local jurisdiction.
• Parking: Many Oregon cities have eliminated parking requirements for ADUs.
• Owner Occupancy: Oregon law limits owner-occupancy requirements.
• Approval Timeline: Streamlined permitting processes in most jurisdictions.

Hillsboro Local Requirements

GatherADU works with Hillsboro homeowners to navigate local building codes and zoning requirements specific to your property and neighborhood.

California law (AB 68, AB 881, SB 9, and subsequent legislation) guarantees your right to build ADUs. Cities cannot:

• Require owner-occupancy for ADUs permitted after 2020
• Require additional parking for ADUs near transit
• Charge impact fees for ADUs under 750 sq ft
• Deny ADUs that meet state minimum standards
• Impose lot coverage limits that prevent a 800 sq ft ADU

If you believe your ADU application is being unfairly denied, California HCD can intervene on your behalf.

Oregon ADU Legislation Overview

Oregon has been at the forefront of ADU-friendly legislation, recognizing ADUs as an important housing solution.

Key Oregon ADU Laws:

• HB 2001 (2019): Required cities to allow ADUs on all single-family residential lots.
• SB 458 (2021): Allowed lot splits for homes with ADUs.

Oregon ADU Benefits:

• Streamlined approval process
• Limited parking requirements
• Flexible rental options

Hillsboro, located in Washington County, Oregon, is a vibrant city known for its tech-driven economy, scenic landscapes, and rich history. As one of the fastest-growing cities in the Portland metropolitan area, Hillsboro offers a blend of suburban charm and urban convenience.

Geography and History

Hillsboro is situated in the Tualatin Valley with 106,612 residents, surrounded by rolling hills and agricultural lands. The city’s history dates back to the 19th century, with a strong foundation in agriculture and early industry. Today, it is a key player in the tech industry, often referred to as the "Silicon Forest."

Local Economy

Hillsboro’s economy is diverse and robust, with several key sectors contributing to its growth:

• Technology: The city is a hub for tech companies, including Intel, which has a significant presence in the area.
• Manufacturing: Includes electronics, precision instruments, and various industrial products.
• Retail and Services: A growing commercial sector with shopping centers, restaurants, and service providers.
• Healthcare: Local medical facilities and healthcare providers are major employers.
• Education: Several schools and educational institutions, including Hillsboro School District and local colleges.

Popular Neighborhoods

Hillsboro offers a range of neighborhoods, each with its own unique characteristics:

• Downtown Hillsboro: Known for its historic charm, local shops, restaurants, and community events.
• Orenco Station: A master-planned community featuring modern homes, parks, and easy access to public transit.
• South Hillsboro: A newer development with family-friendly amenities, parks, and schools.
• Amber Glen: An established neighborhood with well-maintained homes and proximity to major tech employers.
• West Hillsboro: Offers a suburban feel with larger homes and proximity to green spaces.

Real Estate Market

Hillsboro’s real estate market is competitive, with a range of housing options from affordable single-family homes to upscale properties. The market has seen strong growth due to the city’s economic opportunities and quality of life. The relative affordability compared to Portland makes Hillsboro an attractive option for homebuyers and investors.

ADU Regulations in Hillsboro

Hillsboro has implemented specific regulations for Accessory Dwelling Units (ADUs) to address housing needs and support sustainable development:

• Zoning: ADUs are permitted in residential zones and some mixed-use zones, subject to specific conditions.
• Types of ADUs: Both attached and detached ADUs are allowed, including conversions of existing structures and Junior ADUs (JADUs).
• Size Limits:
  • Detached ADUs: Up to 800 sqft for standard ADUs, or up to 1,000 sqft if a lot is greater than 8,000 sqft.
  • Attached ADUs: Up to 50% of the primary dwelling’s living area or 800 sqft, whichever is less.
  • JADUs: Up to 500 sqft.
• Height Restrictions: Detached ADUs are generally limited to 16 feet in height, though exceptions may apply for specific designs.
• Parking: Generally, no additional parking is required for ADUs if the property is located within a specified distance from public transit.
• Owner Occupancy: Owner-occupancy is not required for ADUs, allowing flexibility in rental arrangements.
• Approval Process: ADUs that meet certain criteria may be eligible for streamlined approval processes, including ministerial review.
• Multiple ADUs: On multi-family properties, additional ADUs may be allowed, subject to specific conditions and zoning regulations.
• Impact Fees: Impact fees for ADUs are reduced to encourage development, especially for smaller units.
• Design Standards: ADUs must be designed to be compatible with the primary residence and neighborhood character, including architectural style and materials.

These regulations aim to increase housing options in Hillsboro while maintaining the city’s character and supporting community growth.

Cultural Landmarks and Unique Aspects

Hillsboro is known for several unique features and landmarks:

• Hillsboro Civic Center: A hub for local government, community events, and cultural activities.
• Intel Campus: A major employer and technological landmark, contributing to the city’s reputation as a tech hub.
• Orenco Station: A modern, transit-oriented community that exemplifies Hillsboro’s approach to sustainable development.
• Historic Downtown: Features well-preserved buildings, local shops, and a vibrant community atmosphere.

Hillsboro’s ADU regulations reflect the city’s commitment to addressing housing needs while preserving its unique character. With its growing economy, tech-driven landscape, and diverse community, Hillsboro is well-positioned to benefit from the flexibility and innovation offered by ADUs. The city’s approach demonstrates a forward-thinking strategy to provide diverse and affordable housing options in a dynamic and evolving urban environment.

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