St. Charles County presents an income-versus-carrying-cost tension. The Zillow county observation labeled 2026-06 puts median home value at $378,245 and median asking rent at $1,700 per month. Rent rose faster than price, and the record reports a 5.39% gross yield before costs. That warrants further work by investors able to verify unit-level expenses, while purchasers of flood-exposed homes should be cautious: county figures cannot establish a parcel’s cash flow or insurability.
Market rent, not HUD, supports the reported yield. HUD’s two-bedroom FMR is $1,218 per month, a payment standard rather than an asking-rent estimate. Effective property tax is 1.09%, with median annual tax of $3,480, so tax must be deducted before relying on gross yield. FHFA’s 2025 repeat-transaction HPI rose 4.80% annually, confirming Zillow’s price direction but not measuring a dollar home value; it uses a different method and vintage and must not be combined into a single growth rate.
Realtor.com is MLS listing-market evidence, not sales evidence: median marketing time was 41 days, and 14.35% of listings had price reductions. Its 75.58% pending-to-active ratio and essentially unchanged visible inventory should be read alongside those seller concessions, not as proof of buyer demand. Tax-return migration was positive, while movers in had average income $2,861 higher than movers out. Nonoccupants accounted for 8.07% of 5,654 purchase mortgages, documenting participation but not bidding pressure or all-cash competition.
The 0.19% modeled annual building-value loss aligns with inland flood as the dominant hazard, but county modeling cannot replace a parcel flood zone, elevation, claims history, coverage terms or premium. QCEW shows nearly flat annual covered employment and a higher covered-worker wage at county workplaces—not resident employment or unemployment—and identifies Trade, transportation, and utilities as the largest disclosed private supersector, not the whole economy. Missing closed-sale comps prevent a sale-price conclusion; missing vacancy, operating expenses, condition, lease terms and insurance prevent net-yield and hazard-adjusted cash-flow underwriting.