California ADU Policy Brief
California has made significant progress in reducing barriers to Accessory Dwelling Units through state legislation intended to lower costs and increase housing production.
However, local implementation can still create practical barriers when fees are imposed in ways that are unclear, inconsistent, or not tied to a new or separate utility connection.
Purpose of This Brief
This page provides background on the policy issue, the implementation gap, and the practical effect that local utility and sanitation fees can have on homeowners attempting to build ADUs.
Key point: ADU laws are intended to reduce unnecessary barriers to small-scale housing production. Local fee practices should be clear, consistent, and tied to the actual service or infrastructure being provided.
Implementation Gap
- Some homeowners receive fee information late in the approval or construction process.
- Some fees are applied even where existing infrastructure is used.
- Different agencies may interpret ADU fee limitations differently.
- Homeowners may have limited practical recourse once fees are imposed.
This issue is especially important where an ADU connects through an existing private sewer line serving the main residence, rather than requiring a new direct connection to the utility.
Why It Matters
Unexpected or disputed utility charges can affect whether a homeowner can afford to complete an ADU project. These costs may also undermine the broader purpose of California’s ADU laws: increasing housing supply through smaller, homeowner-led projects.
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