Plain-English meaning
Coverage that may apply to water or waterborne material backing up through sewers or drains, or overflowing from a sump, as defined by the endorsement.
Why it matters
Standard homeowners forms may exclude or limit this event without an endorsement.
Where you may see it
Water-backup endorsements, declarations, basement questions, and claim reports.
What to verify
Trigger, limit, deductible, sump wording, resulting damage, remediation, and exclusions.
Do not confuse it with
Flood, seepage, surface water, or a broken interior pipe.
For policy-specific meaning, read the definition and related provision in the issued policy.