Yes, you will need both endorsements on your policy to be fully covered for water events. Sewer Back-up and Overland Water Endorsements work together to provide you with comprehensive coverage. After the floods of 2013, many insurance companies placed tighter guidelines and increased exclusions on sewer back-up coverage. One major exclusion, for example, is that if overland water enters your home causing flooding, your sewer back-up claim may be denied. By adding both a Sewer Back-up Endorsement and an Overland Water Endorsement to your  insurance policy, you will have comprehensive coverage in the event of a claim.