Permit Reassurances Enabling Direct Improvements for Conservation, Tenants, and Species Act of 2018 or the PREDICTS Act of 2018 This bill amends the Endangered Species Act of 1973 to provide statutory authority for requirements regarding habitat conservation plans, candidate conservation agreements, and safe harbor agreements. Those plans and agreements give nonfederal property owners incentives, such as assurances regarding resource use restrictions, if the owner contributes towards the recovery or conservation of an endangered species, a threatened species, or a species that is a candidate for listing as an endangered or threatened species. Under current regulations, a habitat conservation plan is required for entities to hold an incidental take permit for a project that may result in the incidental taking of an endangered or threatened species. Under candidate conservation agreements and safe harbor agreements, property owners enter into agreements with the Department of the Interior or the Department of Commerce, as appropriate, to address the needs of endangered, threatened, or candidate species in exchange for assurances regarding resource use restrictions that might be imposed if circumstances change. Each incidental take permit, candidate conservation agreement, and safe harbor agreement must contain certain assurances governing permit revocation, changed circumstances, and unforeseen circumstances as prescribed by the bill. The departments may provide grants to individual private landowners to assist the landowners in carrying out candidate conservation agreements or safe harbor agreements.