Since "Dynasty" was filmed in the Filoli mansion (in which the Carrington family lived) only in the pilot episode, the article sheds some light on the Arden Villa in Pasadena, which was used for exterior scenes on "Dynasty" in the show's 3rd and 4th season.
Beyond that, the villa (which is known to prime-time audiences from many shows, including "Knight Rider") appeared only twice - in the 8th season opener (when Blake and the police try to ambush Matthew) and in "The Reunion" mini-series.
One of the show's most iconic scenes - Krystle and Alexis' lilly pond catfight was filmed at the property. The mansion owner and his roommate take a dip in the "fish pond" for the People Magazine feature. Since then the villa changed owners several times.
The property is located at 1145 Areden Road in Pasadena, CA. Scroll down below the Dynasty screencaps featuring the villa for the full article including profiles of Southfork Ranch of 'Dallas' and Spring Mountain Vineyards of 'Falcon Crest.'