San Diego ADUs Rent for a Median $2,250 a Month, More Than Apartments Nearby (October 2026)

Owners building an ADU to rent out all ask the same thing first: what will it bring in? We pulled every closed MLS lease of an ADU or other second unit on a house lot in San Diego County from October 2025 to October 2026. There were 126, on 117 lots. The median rented for $2,250 a month at 500 square feet, and the middle half ran from $1,806 to $2,838.

Size sets the rent

By bedrooms, the median rent was $1,873 for studios, $2,198 for one bedrooms and $3,000 for two bedrooms. Small units earn the most per foot: units under 500 square feet rented for a median $4.72 a square foot, against $3.33 at 750 to 1,200 square feet.

Where it is

Across the areas with 10 or more leases, the median ADU rented for $3,000 in coastal North County (750 square feet), $2,350 in inland North County (665 square feet), $2,248 in central San Diego (490 square feet), $1,995 in East County (475 square feet) and $1,923 in the South Bay (400 square feet). Part of that gap is size: coastal North County had the biggest units. Per square foot, central San Diego led at $4.58 and inland North County was lowest at $3.26.

Against apartments nearby

For 34 of the 126 ADUs, at least 5 apartments or condos of about the same size (within 25%) leased within two miles over the same months. Those ADUs rented for a median $3,000, against $2,450 for the apartments around them, a median premium of 13%. The ADU came out ahead in 31 of the 34. Most ADUs sit among houses, where few small apartments lease, so the rest had too few neighbors to compare.

How we counted

Neither lease record says "ADU", so we matched each lease to its county parcel. A lease counts when the county records the lot as a single family home or a house with a second unit, the lease is 1,200 square feet or less and under 60% of the lot's recorded living area, and the unit has two bedrooms or fewer or its own unit number. Room rentals are left out, and a unit leased again within 60 days (a relisting or a duplicate record) counts once, which removed 5 leases. That catches backyard cottages, garage conversions and guest houses, and likely a few units carved out of a house. Only leases listed on the MLS appear here, and the records don't say whether a unit came furnished. To test an ADU on your own lot, start from the row that matches its size and run it through the cashflow calculator.