Does an ADU Actually Raise My Home's Value in Woodland Hills? Here's the Real Data

Jonathan Lopez, Woodland Hills Realtor | Jim Sandoval Group | CA DRE #02282844 · Updated August 2026

Woodland Hills homeowners with the yard space for it ask a version of this question constantly: if I build an accessory dwelling unit, am I actually raising my home's resale value, or just picking up rental income while I own it? It's a fair question. An ADU is a real construction project, often $150,000 or more, and "it'll add value" gets said a lot without anyone pointing to a number.

What the Data Actually Shows

The Federal Housing Finance Agency tracks appraisal data on every home financed through Fannie Mae or Freddie Mac, and in 2023 it started breaking that data out by whether the property has an ADU. Looking at California specifically from 2013 to 2023, FHFA found that homes with an ADU had a median appraised value of $1,064,000 by 2023, compared to $715,000 for homes without one, a gap of roughly $349,000. More telling than the snapshot is the trend: appraised values on ADU properties grew at an annualized rate of 9.34% over that decade, versus 7.65% for properties without one. That gap in growth rate has been widening since 2018, according to FHFA's own analysis.

A caveat worth being direct about: this is observational data comparing two different sets of homes, not a study that tracked the same houses before and after an ADU was added. Homes with ADUs may also sit on larger lots or in different neighborhoods than homes without them, and FHFA's own writeup says as much, calling for more research at the metro level. What the data does support is that ADU properties in California have not been a drag on value relative to their neighbors without one, and the growth trend has moved in the ADU's favor for several years running.

Why This Is Relevant in Los Angeles Specifically, Not Just Statewide

No public source breaks out ADU appraised value by zip code, so there's no Woodland Hills specific version of the $1,064,000 versus $715,000 comparison. But the volume of ADU activity locally is real: Los Angeles County alone permitted more than 45,000 ADUs in 2023, per Brookings Institution research. That's a market where ADUs are common enough that buyers, appraisers, and agents are used to seeing and valuing them, not a novelty that confuses a comp.

The Cost Side, Because Value Only Matters Relative to What You Spend

Building an ADU in Los Angeles isn't cheap. Cost guides from local ADU builders put a new detached or attached unit at roughly $120,000 to $400,000 depending on size, layout, and finish level, with garage conversions running closer to $100,000. Some builders quote figures as high as $450,000 for larger or more complex projects. That's a wide range, and the right number for any specific property depends on lot conditions, utility access, and design choices, not a single average that applies to every yard in Woodland Hills.

Property Taxes Go Up, But Not on Your Whole House

Under California's new-construction assessment rules, adding an ADU triggers a reassessment of the ADU itself, not the entire property. Your home's existing Prop 13 base year assessment stays untouched; the ADU's own value gets added on top of it and grows under the same 2% annual cap going forward. Typical added tax runs about 1% to 1.5% of the ADU's construction cost per year, so a $200,000 ADU might add roughly $2,000 to $3,000 a year to the tax bill, on top of whatever it costs to build and maintain. This is a different question than why your existing tax bill already looks different from your home's market value, worth understanding on its own before adding new construction to the mix.

How This Fits Woodland Hills' Current Market

As of today, 401 homes are actively listed here, and 101 of them, about 1 in 4, have already had at least one price reduction (Movoto). The median sale price is $1,345,000 with an average 49 days on market. In a market with that much active competition and price movement, a decision to spend $150,000-plus on an ADU should be weighed against what it actually does for a specific home's position in that market, not decided on a general "ADUs are popular" assumption. That's the same reason a generic online value estimate falls short, see how accurate a Zestimate actually is for a related look at why real comps beat automated numbers.

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