California ADU rules · San Diego County
Can I Build an ADU in Santee?
Yes — you can build an ADU in Santee. California's statewide ADU law requires every city, including Santee, to approve a qualifying accessory dwelling unit by right, plus a junior ADU (JADU) on a single-family lot. What varies city to city are the local specifics below.
Can you build one?
ADUs allowed
CA state lawYes — by right
ADUs and JADUs are allowed by right in all residential and mixed-use zones; ministerial approval, no hearing.
Units on a single-family lot
CA state law1 ADU + 1 JADU
At least one ADU and one JADU per single-family lot (a conversion ADU may also be possible).
Units on a multifamily lot
Local ruleConverted ADUs: at least 1, up to 25% of existing units (from non-livable space). Detached ADUs: up to 2 on a lot with a proposed multifamily dwelling, or up to 8 on a lot with an existing multifamily dwelling, not to exceed the number of existing units.
Detached ADUs on multifamily lots are capped at 2 for proposed buildings, up to 8 for existing, but not to exceed the number of existing units.
Junior ADU (JADU)
CA state lawAllowed
Up to 500 sq ft, within the walls of an existing single-family home (single-family lots only).
Size & height
Max detached ADU size
CA state law1,200 sq ft
Statewide default cap for detached new-construction ADUs in the absence of a compliant local ADU ordinance. The unconditional by-right floor a city must always allow is 800 sq ft (see Guaranteed minimum size); a city with a compliant ordinance may set its own ceiling.
Max attached ADU size
Local rule850 sq ft (studio/1-bed) or 1,000 sq ft (2+ beds), but also limited to 50% of the floor area of the existing primary dwelling; never less than 800 sq ft by right.
Both the 50% rule and the 850/1,000 sq ft caps apply; 800 sq ft is always allowed by right.
Guaranteed minimum size
CA state law800 sq ft
An 800 sq ft ADU must be allowed regardless of FAR/lot-coverage caps; a city also cannot cap an attached ADU below 850 sq ft (1,000 for 2+ bedrooms).
Max JADU size
CA state law500 sq ft
Max height
Local rule16 ft
16 ft standard; 18 ft if within ½ mile of major transit or for detached ADU on multifamily lot; up to 20 ft for roof pitch alignment.
Setbacks
Side setback
CA state law4 ft
A city cannot require more than 4 ft side or rear setback; conversions of existing structures are exempt.
Rear setback
CA state law4 ft
Front setback
Local ruleMust meet the zone’s front setback (e.g., 20 ft in R-1, 10 ft in R-14); conversions may have no setback if built in same location/dimensions as existing structure.
Front setback is per base zone; conversions exempt if in same footprint.
Separation from main house
CA state lawNone required
No statewide separation requirement between the ADU and the primary dwelling.
Parking
Parking required
Local ruleUp to 1 space
1 space per ADU or per bedroom (whichever is less); exemptions for transit, historic, conversions, or car share.
Transit parking exemption
CA state lawYes — no parking required near transit & for conversions
No parking may be required within ½ mi walking distance of transit, in a historic district, for an ADU within an existing structure, within one block of car-share, or in certain permit-parking areas.
Garage-conversion replacement parking
CA state lawNot required
When a garage/carport is demolished or converted to build an ADU, replacement parking cannot be required.
Approval, timeline & cost
Approval path
CA state lawMinisterial (by right)
No public hearing or discretionary design review for a qualifying ADU.
Approval timeline
CA state law60 days
The agency must act within 60 days of a complete application — and the ADU is deemed approved if it does not.
Owner-occupancy
Local ruleOnly for a JADU
No owner-occupancy for ADUs; JADUs require owner-occupancy unless JADU has separate sanitation or is owned by public agency/land trust.
Impact-fee waiver
CA state lawWaived under 750 sq ft
An ADU of 750 sq ft or less pays no impact fees (the 750 sq ft threshold itself is exempt under § 66311.5); larger ADUs pay fees proportional to the primary dwelling. JADUs (≤ 500 sq ft) are exempt.
Permits required
Local ruleBuilding permit, Demolition permit (for garage conversion)
Demolition permit for garage conversion is issued concurrently with building permit.
Santee-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Fire sprinklers
Sprinklers required only if primary dwelling requires them.
Historic district
If in a historic district, some additional review may apply.
Santee allows up to 8 detached ADUs on existing multifamily lots (not exceeding the number of units) and applies both a 50% primary dwelling and 850/1,000 sq ft cap for attached ADUs. Parking is required unless exempted by transit or other factors; no owner-occupancy for ADUs, but JADUs generally require it.
Frequently asked questions
Can I build an ADU in Santee?
Yes. California's statewide ADU law requires Santee to approve a qualifying accessory dwelling unit ministerial (by right), plus a junior ADU (JADU) on a single-family lot.
How big can an ADU be in Santee?
A detached ADU of at least 1,200 sq ft must be allowed, and an ADU of 800 sq ft can never be zoned out by floor-area or lot-coverage limits. A JADU can be up to 500 sq ft.
What are the setback requirements for an ADU in Santee?
Side and rear setbacks are limited to 4 ft. Must meet the zone’s front setback (e.g., 20 ft in R-1, 10 ft in R-14); conversions may have no setback if built in same location/dimensions as existing structure..
Is parking required for an ADU in Santee?
Up to 1 space. No parking can be required within ½ mile of transit, for conversions, or for units inside the primary home. When a garage is converted, replacement parking is not required.
How long does ADU approval take in Santee?
A complete application must be acted on within 60 days, with ministerial (by right) — no public hearing or discretionary design review for a qualifying ADU.
Do I have to live on the property to build an ADU in Santee?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Santee Municipal Code §13.10.045, §13.10.050; Ord. 630 (12/10/2025), Ord. 631 (1/14/2026)
- SMC §13.10.045(F)(1)(a)-(d); Ord. 630, 12/10/2025
- SMC §13.10.045(G)(1)(b)
- SMC §13.10.045(D)(7)
- SMC §13.10.045(G)(2)
- SMC §13.10.045(D)(11)
- SMC §13.10.045(D)(6); §13.10.045(E)(3)-(5)
- SMC §13.10.045(H)
- SMC §13.10.045(D)(2)
- Cal. Gov. Code §§ 66310–66342 (ADU Law)
- HCD 2025 Accessory Dwelling Unit Handbook
- Cal. Gov. Code § 66317 (ministerial approval, 60-day deadline)
- Cal. Gov. Code § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- Cal. Gov. Code § 66333 (junior ADUs)
- Cal. Gov. Code § 66321 (size minimums & height)
- Cal. Gov. Code § 66322 (ADU parking; § 66334 covers JADU parking)
- Cal. Gov. Code § 66314 (local ordinance standards)
- Cal. Gov. Code § 66311.5 (impact fees: none for an ADU ≤ 750 sq ft or JADU ≤ 500 sq ft)
Last updated 2026-06-25. This is an AI-assisted summary of Santee's ADU rules, drawn from its published ordinance and California ADU law — general information, not legal advice, and it may be incomplete or out of date. Verify the controlling rule for your specific parcel with Santee Planning before relying on it.
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