This was requested in a previous thread:
From the Davenport City Code, which can be found here.
17.45.050 Temporary signs.
B. 3. Signs may be erected pertaining to the candidacy of federal, state and local elected officials; measures appearing on the ballot of any national, state or local election or caucus; or issues of individual or community concern not exceeding a total of thirty-two square feet and a maximum height of six feet in all zoning districts. Election or caucus signs may be erected not more than forty-five days preceding the election and must be removed within seven days after the election or caucus. Political signs shall be set back a minimum of five feet from any property line. (Emphasis added)
Edit: Also, in case anyone was wondering, the Davenport Primary Election takes place on October 6th.