ADU Impact Fees: El Cajon vs San Diego
How do adu impact fees rules compare between El Cajon, CA and San Diego, CA?
El Cajon and San Diego have similar restriction levels.
El Cajon, CA
San Diego County
El Cajon waives all local impact fees on ADUs under 750 sq ft per California Government Code §65852.2(f)(3). ADUs 750 sq ft or larger pay impact fees proportional to the primary dwelling's square footage. Standard building permit and plan-check fees still apply through the Community Development Department fee schedule, and school district fees follow SB 13 proportional rules.
View full El Cajon rules →San Diego, CA
San Diego County
San Diego exempts ADUs under 750 square feet from all impact fees per California Government Code § 65852.2(f). ADUs 750 sq ft or larger pay impact fees proportionate to the principal dwelling's square footage. Affordable ADUs deed-restricted for low/moderate-income tenants receive additional fee waivers. School fees are separately governed by SB 13 (2019) and state law.
View full San Diego rules →Key Facts Comparison
| Fact | El Cajon | San Diego |
|---|---|---|
| Under 750 sq ft | All local impact fees waived | ALL impact fees waived (state law) |
| 750+ sq ft | Proportional to primary dwelling | Proportional to principal dwelling |
| State Law | Gov. Code §65852.2(f) | Gov. Code § 65852.2(f) |
| School Fees | Proportional (SB 13) | Proportional under SB 13 |
| Water Service | Helix Water District / Otay Water | - |
| Affordable Bonus | - | Additional waivers for deed-restricted ADUs |
Highlighted rows indicate differences between cities.
El Cajon FAQ
Are ADU impact fees waived in El Cajon?
Yes for ADUs under 750 sq ft. California Gov. Code §65852.2(f)(3) preempts all local impact fees on small ADUs. ADUs 750 sq ft or larger pay proportionally based on the principal dwelling's size, not the full single-family rate.
What ADU costs still apply in El Cajon?
Standard building permit fees (construction-valuation based), plan-check fees, and water and sewer capacity charges from Helix Water District or Otay Water District if a new connection is required. Property taxes will reassess on the added improvement value.
San Diego FAQ
Are ADU impact fees waived in San Diego?
Yes for ADUs under 750 sq ft — all local impact fees are waived by state law (Gov. Code § 65852.2(f)). ADUs 750 sq ft+ pay proportional fees, not full single-family rates.
How much can I save by building under 750 square feet?
Impact fees in San Diego typically total $10,000–$30,000 for a new single-family unit. Building under 750 sq ft eliminates this entirely. Permit fees, plan-check, and utility service fees still apply.
Compare other topics
See how El Cajon and San Diego compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool