- Backyard ADU on owned lot: $280K–$330K all-in, $24K–$32K typical annual gross rent, 8%–11% gross yield on cash, payback 9–14 years if cash-funded.
- Small LA rental condo (2BR, $475K–$525K range): roughly 4.5%–5.5% cap rate after HOA and property tax reset, leveraged cash-on-cash 6%–9% at 75% LTV, payback 14–20 years.
- Three structural advantages of the ADU: no Prop 13 base-year reset on new acquisition, no HOA, no separate property management contract for the first tenant.
- Three structural advantages of the condo: liquidity, geographic diversification, leverage at investment-property rates without touching the homestead.
- The decision usually turns on three variables: do you want concentration on one parcel, are you willing to be the landlord next door, and is your existing mortgage rate locked below 5%.
The Two Paths
Before comparing outcomes, it helps to be precise about what each path actually costs and what it produces.
Build a backyard ADU on the lot you already own
Buy a small rental condo in the same metro
Side-by-Side Comparison
| Variable | Backyard ADU (600 sqft detached) | Small LA Rental Condo (2BR) |
|---|---|---|
| Cash deployed | $280K–$330K (or $30K + HELOC) | $140K–$160K, financed |
| Asset price | Build cost = asset cost | Purchase + closing + prep |
| Gross annual rent | $22,800–$31,200 | $33,600–$40,800 |
| Gross yield on cash | 8%–11% on cash | 7%–9% on cash, leveraged |
| Operating overhead | Utilities split or sub-metered, no HOA | HOA $4,200–$7,800/yr + property mgmt |
| Year-one cash flow (financed) | $5K–$8K positive (HELOC scenario) | $7K–$14K negative |
| Property tax exposure | No Prop 13 reset on existing parcel | Full Prop 13 reset at new base-year |
| Liquidity | Illiquid; tied to primary residence sale | MLS-listable, 30–90 day sale window |
| Tenant proximity | On your lot — you see them daily | Separate building, separate problem |
| Capital concentration | All on one parcel | Splits exposure across two assets |
Three Variables That Decide It
Most of the numbers above favor the ADU on yield and near-term cash flow. The condo wins on liquidity and concentration risk. The three variables below are where the decision actually gets made on a per-homeowner basis.
Capital concentration vs. diversification
The ADU concentrates risk on one parcel. If LA Westside zoning shifts, a neighbor sues over new construction, or the lot floods — all of your invested capital sits in one location. The condo splits the exposure. A natural-disaster event hitting your primary residence doesn’t take out the condo, and vice versa.
The flip side: the ADU shares the upside of the primary residence’s land value. LA dirt has historically outperformed condo improvements. Over a 20-year hold, the parcel under your house typically appreciates faster than the condo unit a few miles away. Concentration cuts both ways.
The landlord-next-door reality
Most homeowners underestimate what it feels like to have a tenant 30 feet from their kitchen window. The good version: a quiet 60-year-old retiree on a year lease, predictable, low-friction. The hard version: a tenant whose habits ripple into your daily life — noise, trash, visitors, the argument at 11pm you can hear through your bedroom wall.
The condo tenant lives somewhere else. You handle their problems through a property manager. There’s a separation of physical space and emotional bandwidth. For some homeowners that separation is worth giving up the higher yield. For others it isn’t.
The lock-in factor
Roughly 80% of California homeowners hold mortgages below 5% (FHFA National Mortgage Database). If yours is one of them, the ADU side of this comparison gets stronger. A HELOC on the existing property preserves the sub-5% rate; the condo purchase requires a separate investment-property loan at 7.25%–7.75%. The interest-cost gap over a 10-year hold often runs $40,000–$90,000 in the ADU’s favor on a $300K project.
If your existing mortgage rate is above 6.5%, the calculus shifts. The lock-in savings shrink, the condo’s separate-asset thesis gains weight, and the decision becomes closer to a coin flip on personal preference.
The Tax Exposure
The Prop 13 base-year reset is the single most under-discussed variable in this comparison. Buying a rental condo in LA triggers a full reassessment at the purchase price. A $500K condo carries roughly $6,250/year in property tax at California’s 1.25% effective rate.
The ADU on your existing property does not reset the existing home’s Prop 13 base. The ADU itself gets assessed at construction value (not full property value), and the LA County assessor typically adds $280K–$330K of new improvement value to the existing assessment.
That’s a $2,000–$2,700/year delta, every year. Over a 20-year hold, the ADU’s tax advantage compounds to $40,000–$54,000 in retained cash flow. Verify your specific assessor treatment with LA County Office of the Assessor and a CPA — assessment methodology varies by parcel.
This is not tax advice. ADUscale is not a tax advisor — verify your situation with a CPA before acting on it.
When Each Path Wins
ADU wins when…
- Your primary mortgage is locked below 5%.
- The lot is buildable without major hillside or soils overlay.
- You expect to hold the primary residence for 10+ years.
- You value the Prop 13 base-year protection.
- You’re willing to be the landlord next door.
Condo wins when…
- Your primary residence is overleveraged or has a rate above 6.5%.
- You want geographic diversification across LA submarkets.
- You don’t want a tenant on your property, full stop.
- You value the liquidity of an MLS-listable asset.
- You’re already at the CLTV ceiling (no room for HELOC).
ADU vs. Condo Investment, LA 2026
LA City has issued at least 26,862 ADU permits since 2016 legalization per CA YIMBY ADU Reform Retrospective.
California 30-year conforming rate: ~6.25% in mid-2026; investment-property loans price 100–150 bps higher per Federal Reserve H.15 and Bankrate.
~80% of California homeowners hold mortgages below 5% per FHFA National Mortgage Database — the structural reason ADU finance math beats new-acquisition math for most LA homeowners.
LA County effective property tax rate: ~1.25% including base 1% Prop 13 plus voter-approved bond and parcel taxes per LA County Office of the Assessor.
Typical LA condo HOA: $350–$650/month in non-luxury submarkets, $800–$1,400 in newer high-rise buildings.
ADU Prop 13 tax advantage over 20-year hold: $40K–$54K in retained cash flow vs. condo purchase at equivalent all-in cost.
ADU vs. Apartment Investment in LA
We’ve run this comparison on roughly 60 written Feasibility & Risk Assessments in the last 12 months. About 1 in 7 of those reports recommend not building — usually because the lot can’t support a viable ADU footprint, the contractor pool is too thin in that ZIP, or the financing math doesn’t pencil against the homeowner’s specific equity position.
Sometimes the right answer is not to build — and we say that clearly, before any money moves. If your numbers are closer to the condo column than the ADU column, we’ll tell you in the Feasibility report.