Regulatory Certainty Act of 2017 This bill amends the Federal Water Pollution Control Act (commonly known as the Clean Water Act) to limit the period during which the Environmental Protection Agency (EPA) may prohibit the specification, or restrict the use, of an area as a disposal site for discharges of dredged or fill materials into waters of the United States to the period that: begins on the date that the U.S. Army Corps of Engineers provides notice to the EPA that the Corps of Engineers has completed all procedures for processing an application for a permit for dredged or fill material and is ready to determine whether the permit should be issued, and ends on the date that the Corps of Engineers issues the permit. The Corps of Engineers must ensure that the period consists of at least 30 consecutive days. The Corps of Engineers may issue a permit for dredged or fill material only after the Corps of Engineers provides notice to the EPA.