In addition to State rules and regulations included in the Oregon Revised Statutes and Secretary of State publications, referendum petitions in the City of Portland are also governed by provisions of the Portland City Code. The main distinguishing characteristics of City referendum petition requirements are:

• Referendum petitions may be placed only on regular election ballots - unless the Council finds that the public interest would be harmed by waiting. In this situation, the Council may call for a special election at the next available date or call for a special election at an election date when other measures are on the ballot thus reducing the cost.

• Perfected petitions, including the required signatures, must be filed within 30 days of council action.

• Referendum petitions must be signed by a number equal to or greater than 6 percent of the number of electors registered in the city on the date of the primary municipal election immediately preceding the date the prospective petition is filed. A franchise ordinance requires only 2,000 signatures.

• Referendum petitions filed after May 15, 2018 and until May 19, 2020 require 25,092 valid City of Portland registered voter signatures, which represents 6 percent of registered voters in the City of Portland at the May 15, 2018 Primary Election in the City of Portland. Franchise referendum petitions require 2,000 valid Portland voter signatures to qualify to the ballot. 

• Chief Petitioners must be registered voters of the City.

• As with all petitions, the Auditor must certify approval of the prospective petition, and the City Attorney must draft the language that goes on the ballot. Because of the short time limit for gathering signatures, petitioners with a referendum petition do not have to wait for the City Attorney to draft the ballot title before collecting signatures. The chief petitioner may use the title of the ordinance as it was enacted by City Council.