Contra Costa County

Contra Costa County sits at a gross rent-to-price ratio of 0.0453, which annualizes to roughly 4.5% before a single expense hits the ledger. At a $768,394 median purchase price and $2,902 median rent, the market pencils out to a 2.94% cap rate and a cash-on-cash return of negative 14.54% on a 20% down payment at 6.85%. Monthly mortgage alone runs $4,028, estimated expenses add another $1,016, and rent covers only $2,902 of that $5,044 combined carry, producing a negative $2,142 monthly cash flow on the model assumptions. The county scores 38 out of 100 on cash flow and 47 on appreciation, landing it firmly in appreciation territory, though even that score is modest. Home prices are down 0.53% year-over-year, so even the appreciation thesis requires patience rather than near-term conviction. Nationally, Contra Costa ranks 764th out of 1,000 counties analyzed, sitting at the 2nd percentile overall.

The numbers here describe a market for one narrow buyer type: someone who accepts negative carry in exchange for long-run Bay Area appreciation and is not depending on the rental income to service the debt. A pure cash-flow buyer has no business here. The $2,142 monthly shortfall means the investor is writing a check every month, and a cash-on-cash of negative 14.54% means you are losing roughly $1 in annual cash for every $6.88 deployed as a down payment. A value-add operator could compress that gap if rents can be pushed above the $2,902 median, but the entry price leaves little margin for error on renovation costs at these cap rates. The stability score of 50 is the strongest sub-score in the set, which at least argues that the negative cash flow is unlikely to worsen dramatically from a demand shock, but it does not eliminate it.

The tax and insurance carry deserves its own line in your underwrite. Combined monthly tax and insurance runs $576, using a state-average effective property tax rate of 0.73% and an insurance rate of 0.17%, which together account for roughly 11% of the total monthly carry. California's 0.73% state-average effective rate lands in the normal range by national standards and is not a deal-breaker on its own, but at a $768,394 price point it still generates $5,609 in annual property taxes and $1,306 in annual insurance. That $576 monthly figure is baked into the $1,016 estimated expenses above, so no double-counting, but investors running their own sensitivity scenarios should remember this is a state-average estimate and the actual Contra Costa or township-level rate may differ.

The concentration risk here is significant and worth naming plainly. Contra Costa's investment case rests almost entirely on its adjacency to the San Francisco Bay Area labor market. If remote work permanently reduces the premium workers will pay to live within commuting distance of San Francisco and San Jose, the appreciation thesis loses its primary engine. With prices already down slightly year-over-year and an affordability index of 8 out of 100, the pool of potential owner-occupant buyers who could underwrite future price appreciation is constrained. High carrying costs relative to median household incomes in the region have historically acted as a ceiling on how fast prices can run, even in strong job cycles.

Against its comparison set, Contra Costa is actually the most favorable on the rent-to-price ratio. San Francisco County shows a 0.0355 ratio on a $1.245 million median price, generating a worse cash flow profile despite $3,680 in median rent. Ventura County at 0.0411, Santa Barbara at 0.0410, and Monterey at 0.0401 all trail Contra Costa's 0.0453 on yield. Trinity County at $245,831 median is a completely different market with no rent data provided, so a direct comparison is not possible. On overall score, all five neighbors cluster between 35 and 37, meaning Contra Costa at 37 is essentially tied with San Francisco and at or above the others. The practical reason to choose Contra Costa over San Francisco is the lower absolute price and slightly better rent yield. The reason to choose it over Ventura, Santa Barbara, or Monterey is the same: better gross yield at a lower entry price, assuming an investor is committed to the California Bay Area thesis specifically. If the goal is simply to find the least-bad cash flow among California coastal counties, none of these markets solve the problem, and an investor willing to leave the state entirely will find dramatically better yield-to-price ratios elsewhere.