1980 McDowell won the 1980 Democratic Primary and won the November 4, 1980 General election with 6,354 votes against Republican nominee Sandra Kaufmann.
1982 McDowell won the 1982 Democratic Primary and won the three-way November 2, 1982 General election with 7,239 votes against Republican nominee Richard Bugbee and Libertarian candidate Susan Bissell.
1986 McDowell was unopposed for both the September 6, 1986 Democratic Primary and the November 4, 1986 General election, winning with 5,946 votes.
1990 McDowell won the 1992 Democratic Primary and won the November 6, 1990 General election with 5,467 votes against Republican nominee Paul Parets.
1992 McDowell and Parets were both unopposed for their September 12, 1992 primaries, setting up a rematch; McDowell won the November 3, 1992 General election with 8,808 votes against Parets.
1996 McDowell won the September 7, 1996 Democratic Primary with 2,368 votes against Thornton Carroll, and won the November 5, 1996 General election with 7,883 votes against Republican nominee Gary Linarducci.
2000 McDowell was unopposed for the September 9, 2000 Democratic Primary and won the November 7, 2000 General election with 8,970 votes against Republican nominee Lee Murphy.
2002 McDowell won the September 10, 2002 Democratic Primary with 1,388 votes, again against his 1996 challenger Thornton Carroll. Lee Murphy was unopposed for his primary, setting up a rematch; McDowell won the November 5, 2002 General election with 7,646 votes against Murphy.
2006 McDowell won the four-way September 12, 2006 Democratic Primary with 1,477 votes against a field that included Charles Potter, Jr. and Thornton Carroll, his challenger from 1996 and 2002. McDowell won the three-way November 7, 2006 General election with 8,300 votes against Republican nominee Gregory Chambers and Independent candidate Tyler Nixon.
2010 McDowell was unopposed for both the September 17, 2010 Democratic Primary and the November 2, 2010 General election, winning with 11,862 votes.
2012 McDowell won the three-way September 11, 2012 Democratic Primary with 2,342 votes against former state RepresentativeDavid Brady and another challenger. McDowell won the three-way November 6, 2012 General election with 15,155 votes against Independent candidate Robert Clark and Libertarian candidate Brian Lintz.