Does water on knee cause swelling in calf?

It may: Swelling in a leg can be commonly seen from knee related problems, with or without injuries and medical causes such as poor circulation, inflammation, and constriction from a brace or cast. However, sometimes you can get a clot in your leg that can cause swelling in the calf. Go to er immediately to rule out a clot as this can be be fatal if left untreated.