The City of Santee publishes one of the clearest ADU guides in the county. Here is what it says — sizes, setbacks, fees, and the process, straight from the guide.
Summarized from the City of Santee's official ADU Guide (Understanding ADUs in the City of Santee, City of Santee, Version 2) — nothing here comes from aggregators or other cities' rules. Rules change; confirm the current standards with the city before relying on them.
| Types covered | Attached ADUs, detached ADUs, conversions of existing structures, and JADUs — under Santee Municipal Code §13.10.045 and California Government Code §§66310–66344. |
| Max size | Attached: 800–1,200 sq ft. Detached: 800–1,200 sq ft. Conversion: the existing structure plus up to 150 sq ft for entry. JADU: 500 sq ft. |
| Height | Detached: 16 ft standard; 18–20 ft within a half-mile walking distance of a major transit stop (up to 20 ft to match roof pitch). Attached: per the zoning district. |
| Setbacks | 4 ft side and rear for new attached and detached ADUs. Conversions: safety setbacks only. |
| Parking | Not required for attached or detached ADUs under 800 sq ft or near transit. Conversions: no parking required. |
| Kitchen & entrance | ADUs require a full kitchen; JADUs a kitchen or efficiency kitchen. Both require an exterior entrance. A JADU must be contained entirely within a single-family residence or attached garage in a single-family district. |
| Owner occupancy | Not required for ADUs. Required for a JADU — or the associated single-family home — when sanitation is shared. |
| Rentals | Minimum 30-day rentals. Short-term rentals are not allowed in the City of Santee. |
| Separate sale | The City does not allow the sale of ADUs or JADUs. |
| Fees | ADUs under 750 sq ft are exempt from impact fees. School fees may apply to ADUs over 500 sq ft. |
| Sprinklers | Required only if the primary dwelling has or requires them. |
Published ranges by type, the educational estimator, cost drivers, and fee notes.
Read the guide →Eight quick questions and a plain-language likely / maybe / talk-to-the-city result.
Read the guide →Santee's neighbor publishes less online — what El Cajon's official site confirms is here.
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