Synopsis As Introduced Amends the Counties Code. Changes the application of specified provisions concerning stormwater management in the area served by the Northeastern Illinois Planning Commission to those located in the area served by the Chicago Metropolitan Agency for Planning. Authorizes counties containing all or a part of an urbanized area (rather than only 9 specified counties) to adopt stormwater management plans by referendum. Requires a county to adopt and enforce a floodplain management ordinance or a stormwater management ordinance that has been approved by the Office of Water Resources of the Department of Natural Resources and designate a Certified Floodplain Manager before the county may submit a referendum question to the electors for an annual tax. Prohibits a county from levying the tax if they are not in full compliance with specified provisions. Provides for specified special districts to be represented on the stormwater management planning committee in specified counties. Provides that a county's minimum standards for floodplain and stormwater management should have an emphasis on the use of cost-effective solutions to flooding problems. Provides that the stormwater management plans shall evaluate flooding problems caused by urban flooding. Defines "urban flooding". Provides that a stormwater management planning committee may make grants to units of local government, not-for-profit organization, and landowners under specified conditions. Provides that a municipality receiving grant moneys must have adopted an ordinance requiring actions consistent with the stormwater management plan. Makes other changes. Makes similar changes to provisions regarding DuPage and Peoria counties.