The following images (taken from WeatherUnderground.com) show the latest Doppler Radar Rainfall Estimates across the Washington Region.
Washington Region
Washington Metro Area
The Northern Virginia suburbs from Woodbridge to Dale City/Quantico/Triangle and extending just southward into north Stafford saw impressive totals of 4 to 8″ of rain. Garrisonville, Aquia Harbor and Quantico really got pummeled with a stripe of 6 to 8″ of rain! 
The rest of Northern Virginia saw lighter amounts, but a general beneficial rain with most spots receiving a solid inch with upwards of 4″ in several communities in Fairfax and Loudoun counties (note that the data surrounding the actual radar beam at Dulles is skewed meaning more rainfall actually fell in places immediately around the doppler site such as Brambleton, Poolesville, Dulles Airport and Chantilly):
Southern Maryland also got hammered extremely hard with most locations picking upwards of 4 to 8″ of rain! (Notice the maroon colors right across central Calvert county where 6 to 8″ of rain has fallen so far). About 2 to 3 months worth of rain in several days!
DC Storms 