3.7  Effective dates of Acts and resolutions.
  1.  All Acts and resolutions of a public nature passed at regular sessions of the general assembly shall take effect on the first day of July following their passage, unless some other specified time is provided in an Act or resolution.
  2.  All Acts and resolutions of a public nature which are passed prior to July 1 at a regular session of the general assembly and which are approved by the governor on or after July 1, shall take effect forty-five days after approval. However, this subsection shall not apply to Acts provided for in section 3.12 or Acts and resolutions which specify when they take effect.
  3.  All Acts and resolutions passed at a special session of the general assembly shall take effect ninety days after adjournment of the special session unless a different effective day is stated in an Act or resolution.
  4.  An Act which is effective upon enactment is effective upon the date of signature by the governor; or if the governor fails to sign it and returns it with objections, upon the date of passage by the general assembly after reconsideration as provided in Article III, section 16 of the Constitution of the State of Iowa; or if the governor fails to sign or return an Act submitted during session, but prior to the last three days of a session, on the fourth day after it is presented to the governor for the governor’s approval. An Act which has an effective date which is dependent upon the time of enactment shall have the time of enactment determined by the standards of this subsection.
  5.  A concurrent or joint resolution which is effective upon enactment is effective upon the date of final passage by both chambers of the general assembly, except that such a concurrent or joint resolution requiring the approval of the governor under section 262A.4 or otherwise requiring the approval of the governor is effective upon the date of such approval. A resolution which is effective upon enactment is effective upon the date of passage. A concurrent or joint resolution or resolution which has an effective date which is dependent upon the time of enactment shall have the time of enactment determined by the standards of this subsection.
  6.  Unless retroactive effectiveness is specifically provided for in an Act or resolution, an Act or resolution which is enacted after an effective date provided in the Act or resolution shall take effect upon the date of enactment.
  7.  Proposed legalizing Acts shall be published prior to passage as provided in chapter 585.
  8.  An Act or resolution under this section is also subject to the applicable provisions of Article III, sections 16 and 17 of the Constitution of the State of Iowa.
[C51, §22; R60, §25; C73, §34; C97, §37; C24, 27, 31, 35, 39, §53; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §3.7]
87 Acts, ch 1, §1; 2006 Acts, ch 1010, §2
Iowa Constitution, Art. III, §26 
For the effective dates of Acts and resolutions prior to the enactment of 87 Acts, ch 1, §1, effective February 19, 1987, see Code 1987, Code 1966, and prior Codes 
Acts of private nature, §3.11