They bring affordable options and income for homeowners but also more traffic, noise, and parking issues. Are they worth it?
Accessory Dwelling Units (ADUs) have become a prominent feature across San Diego neighborhoods, transforming backyards and properties throughout the city. These secondary housing units—often called granny flats, in-law units, or backyard cottages—have sparked intense debate among residents, developers, and city officials about the future of housing in America's Finest City.
As San Diego continues to face a severe housing crisis, ADUs represent one strategy to increase housing supply without building large apartment complexes. However, their rapid proliferation has led to growing concerns about neighborhood character, infrastructure capacity, and quality of life for existing residents.
The Benefits: Making the Case for ADUs
Addressing the Housing Crisis
San Diego desperately needs more housing across all price points. ADUs represent a relatively quick way to add units to the market without massive redevelopment projects. They help increase housing supply in established neighborhoods with existing infrastructure, potentially helping moderate housing costs.
Creating Affordable Housing Options
The ADU bonus program specifically incentivizes the creation of income-restricted affordable units, which San Diego urgently needs. These units provide housing opportunities for lower-income residents in neighborhoods that might otherwise be unaffordable to them.
Enabling Homeowner Income and Wealth Building
For homeowners, ADUs can provide a significant income stream. A rental ADU can help offset mortgage costs, property taxes, and maintenance expenses. This additional income can be particularly valuable for retirees on fixed incomes or families struggling with San Diego's high cost of living.
Efficient Use of Existing Infrastructure
Building ADUs in established neighborhoods leverages existing infrastructure like roads, water lines, and schools, potentially making them more cost-effective than greenfield development on the urban fringe.
Environmental Benefits
Increasing density in existing neighborhoods, especially near transit, can reduce car dependency and associated greenhouse gas emissions. Smaller living spaces also typically consume less energy than larger single-family homes.
The Concerns: Community Pushback Against ADU Expansion
Parking and Traffic Impacts
In many Transit Priority Areas, ADUs are exempt from parking requirements, based on the assumption that residents will use public transit. However, critics argue that San Diego's transit system isn't comprehensive enough to eliminate car ownership, leading to increased street parking competition and traffic congestion.
As one community planning group noted, "Any development inside a TPA will still have no parking requirements," despite concerns that many residents will still own cars due to the limitations of San Diego's transit system.
Neighborhood Character Concerns
Many long-established neighborhoods were designed as lower-density communities with consistent architectural styles. Some residents argue that multi-unit ADU developments fundamentally alter the character of these areas, particularly when multiple two-story units are built with minimal setbacks from property lines.
Residents in neighborhoods like College East, Talmadge, and Clairemont have organized against what they call "backyard monstrosities" that loom over adjacent properties.
Infrastructure Strain
Critics question whether existing infrastructure—including water and sewer systems, roads, parks, and emergency services—can accommodate significant population increases without substantial upgrades. They argue that the city is allowing density without corresponding infrastructure investments.
Safety Concerns
In May 2025, the Community Planners Committee recommended that the ADU bonus program should not apply in Very High Fire Hazard Severity zones or on streets with a single egress point, like cul-de-sacs, due to evacuation concerns during emergencies.
Limited Affordability Impact
While the program requires some units to be affordable, critics contend that the overall number of affordable units created is too small to justify the neighborhood impacts. They argue that most units end up as market-rate rentals that don't meaningfully address affordability challenges.
