1-Bedroom ADU rental ROI in Shoreline

Frequently asked

• What ROI can I expect on a Shoreline ADU at $2,200–$2,800/mo rent?

  At $2,200–$2,800/mo long-term rent on a $210K all-in 600 sqft DADU in Shoreline, unleveraged cap pencils 4.8–6.2% in 2026. Leveraged cash-on-cash (75% HELOC at 8.5%) is 7.5–11%. Tax benefits (depreciation, mortgage interest, operating expense write-offs) typically add 1.5–2.3% to after-tax yield for owners in the 32–37% federal bracket. Mid-term rentals (30–90 day) on the same unit raise gross by 12–22% but add management complexity. 10-year IRR including appreciation lands 9–14% in our Shoreline rental hold models.

  Go deeper: Shoreline ADU cost breakdown→

• How long until a Shoreline ADU pays for itself?

  Cash-on-cash payback (rent net of all expenses recovers down payment + closing) on a Shoreline ADU at $2,200–$2,800/mo rent typically lands year 8–11 on a leveraged build, year 14–18 on all-cash. But payback is the wrong metric — total return including appreciation, principal paydown, depreciation shield, and Section 121 exclusion of up to $250K/$500K capital gain on sale is what matters. With those included, Shoreline ADUs typically hit IRR breakeven (above your cost of capital) by year 3–4 on a leveraged build.

  Go deeper: Shoreline ADU overview→

• Should I rent my Shoreline ADU long-term, mid-term, or short-term?

  Default to long-term (30+ days) for highest after-tax IRR in Shoreline because of WA's lack of state income tax and no STR management overhead. Mid-term (30–90 days, often furnished, traveling nurses or insurance-displaced) is the sweet spot in Shoreline submarkets near Swedish, Overlake, UW Medicine — adds 12–22% gross with manageable turn frequency. Short-term (≤30 days) faces Shoreline-specific permitting friction and platform fees that erode the apparent premium; only recommended in very specific Shoreline sub-markets near tourist anchors.

  Go deeper: Read: Long-term vs. short-term rental ADU in Seattle→

• What's the expected appreciation on a Shoreline ADU?

  Shoreline's 10-year median single-family appreciation (FHFA index) runs 5.8–7.2%/yr. Adding a permitted, separately-metered ADU typically adds 30–50% to parcel value at sale — appraisers value via either income approach (cap rate on rental NOI) or sales comp. The marginal value-add ratio (parcel-with-ADU vs parcel-without) is 1.18–1.32 in Shoreline based on our 2024–2025 sales comp pulls. Expect appreciation to track the broader Shoreline market post-build.

  Go deeper: Shoreline ADU overview→

• Does a Shoreline ADU make sense if I plan to sell in 5 years?

  Math depends on entry price vs market spread. Owner-occupants who build for personal use (in-law, aging-in-place) usually recoup 75–95% of build cost at 5-year sale; the gap is the cost of personal use. Investors building for rental should not exit in 5 years — too short to capture full IRR after closing costs and cap-rate compression risk. The right Shoreline ADU horizon is 10+ years; 7+ if you anticipate refinancing or selling into a yield-hungry market.

  Go deeper: Shoreline ADU overview→

• What are typical Shoreline ADU operating expenses?

  Annualized opex for a turn-key Shoreline long-term rental DADU: property tax increment $1,900–$3,100, insurance increment $400–$700, utilities (if landlord-paid; typically tenant-paid via separate meters) $0–$1,200, maintenance reserve 5% of rent, management 8% of rent if outsourced, vacancy 5% of rent. Total opex 28–34% of gross rent, leaving 66–72% NOI. Self-managed owners can compress to 22–26% but trade time for margin.

  Go deeper: Shoreline ADU overview→

• How do I value a Shoreline ADU for sale?

  Two methods to triangulate: (1) sales comp — pull arm's-length sales of ADU-equipped Shoreline parcels within 1 mile, 12 months; (2) income approach — annual NOI / cap rate (currently 5.5–6.8% in Shoreline for stabilized 1BR rentals). The two should converge within 8–12%. Appraisers in Shoreline now apply both and weight toward the higher value when sales comps are thin. Bring both packets to listing.

  Go deeper: Shoreline ADU overview→

• What's the Shoreline ADU rent trajectory through 2030?

  Long-term Shoreline rent growth from 2014–2024 averaged 4.6%/yr including the 2020 dip. Forward-looking, with WA's housing supply catching up under HB 1110 (middle housing) and HB 1337 (ADUs), expect Shoreline 1BR rent growth to moderate to 2.8–3.8%/yr through 2030. That still beats CPI inflation by ~120 bps, which preserves real-rent escalation on Shoreline ADU pro formas. Underwrite at 3% to be conservative.

  Go deeper: Shoreline ADU overview→

• Is leveraged Shoreline ADU yield better than unlevered?

  Yes, currently. At 75% LTV, 8.5% HELOC, $210K build, $2,500/mo rent, after-debt cash flow lands $480–$720/mo (3.0–4.5% cash-on-cash before tax) vs unlevered 4.8–6.2% cap. Leverage looks worse on cap-rate math but better on cash-on-cash because the debt-service spread to gross rent is positive after ~year 3 as rent compounds against fixed-rate debt. Inverts only if HELOC variable rate spikes above ~10.5%.

  Go deeper: Shoreline ADU overview→

• What's the depreciation benefit on a Shoreline ADU?

  Residential rental real estate depreciates over 27.5 years straight-line (IRC §168). On a $210K build with land allocated to primary parcel, depreciable basis is roughly $180–$210K. Annual depreciation deduction: $6,500–$7,600. At a 32% federal bracket that shields $2,080–$2,432 of taxes per year — a meaningful boost to after-tax IRR. Cost segregation can accelerate components (appliances, flooring, cabinetry) into 5–7 year buckets, lifting early-year deductions by 30–40%.

  Go deeper: Shoreline ADU overview→