An ADU that rents for $3,000 a month does not add the same value on every lot. The method the appraiser uses depends on how many units the property ends up with, and that one fact decides whether your ADU is a cash-flow play or a value play.
One to three units: sales comps
A house with an ADU, or a house with an ADU and a JADU, is appraised against comparable sales. The ADU is an adjustment line, and in most California markets that adjustment is well below the cost to build for the first year or two, because appraisers need closed comps with ADUs to support it. The return comes from rent and, over time, from comps catching up. Lenders will typically count 75% of the ADU's market rent as qualifying income on a refinance.
Five or more units: the income approach
At five units the property is commercial multifamily and is valued on net operating income divided by a cap rate. Here every dollar of ADU rent is capitalized immediately. The math Parcy uses:
- Gross rent minus 5% vacancy equals effective gross income.
- Effective gross income minus 35% operating expenses equals NOI.
- NOI divided by the market cap rate equals value.
A $3,000 ADU: $36,000 gross, $34,200 effective, $22,230 NOI, which at a 5.5% cap rate is about $404,000 of value. This is why SB 1211 matters so much: eight of those on one lot is $3.2 million of value for roughly $2.4 million of construction.
Four units: the blend
Fourplexes sit in between. Residential lenders finance them on comps; investors buy them on income. Parcy uses a 60% income, 40% comps weighted blend at four units, which tracks how fourplexes actually trade in Southern California.
What rents are ADUs getting in 2026?
| Unit | Los Angeles | Orange County | San Diego | Bay Area |
|---|---|---|---|---|
| Studio / JADU, 400 to 500 sq ft | $1,700 to $2,100 | $1,900 to $2,300 | $1,800 to $2,200 | $2,000 to $2,600 |
| 1 bed, 600 to 750 sq ft | $2,200 to $2,900 | $2,400 to $3,000 | $2,300 to $2,900 | $2,600 to $3,400 |
| 2 bed, 800 to 1,200 sq ft | $2,800 to $3,800 | $3,000 to $3,900 | $2,900 to $3,700 | $3,300 to $4,400 |
These are ranges for new construction in decent neighborhoods; Parcy replaces them with live comps within a short radius of your lot. Run your address.
Frequently asked questions
Does an ADU increase property value?
Yes, but how much depends on the unit count. At one to three units the ADU is a comps adjustment; at five or more units its rent is capitalized directly into value.
What vacancy and expense assumptions does Parcy use?
5% vacancy and a 35% operating expense ratio on the income approach.
Informational only. Not legal, architectural, or investment advice. Confirm current rules with your local planning department.