$612,000 buys the median home in Washington right now. With 20% down, that's a $122,400 down payment and a $489,600 loan, set against a $90,471 median household income.
Property taxes in Washington run 0.56% of assessed value, below the 1.1% national average. On the median home, that's $3,427 a year, or $286 added to the monthly payment.
Between the $3,649/month mortgage payment and District of Columbia's state income tax, your real housing cost calculation needs your after-tax number, not your gross salary.
Beyond housing, Washington's cost of living index sits at 160 (national average = 100), running above the national baseline for groceries, transportation, and everyday services.