Coverage explainer
Water backup coverage: the cheapest endorsement most homeowners are missing.
Sewer backups and sump pump failures are the #1 cause of denied basement-water claims. They're excluded from standard policies — and the fix costs less than a streaming subscription.
Common policy exclusion
Standard HO-3 language: "We do not insure for loss caused directly or indirectly by water or water-borne material which backs up through sewers or drains or which overflows or is discharged from a sump, sump pump or related equipment."
What water backup actually covers
- Sewer line backups (city main backing up into your home)
- Sump pump failure or overflow
- Drain backups (floor drain, basement bathroom, washing machine)
- Damage to flooring, drywall, baseboards, furniture, HVAC, water heater
- Cleanup, dehumidification, and mold remediation (within sub-limits)
What it doesn't cover
Surface flooding from heavy rain, river overflow, or storm surge — that's flood insurance (separate NFIP or private policy). Also excluded: gradual leaks, seepage through the foundation, and damage from a sump pump you knew was broken and didn't fix.
$5k limit
Bare minimum. Covers a small backup with unfinished basement.
$25k limit
Reasonable floor for any finished basement.
$50k+ limit
Recommended for high-value finishes, HVAC in basement, or stored valuables.
Frequently asked
What is water backup coverage?
Water backup coverage is an optional homeowners insurance endorsement that pays for damage caused by water that backs up through sewers, drains, or sump pump overflow/failure. It is NOT included in a standard HO-3 policy — you have to add it.
Is sewer backup covered by homeowners insurance?
Not by default. Standard HO-3 policies specifically exclude water that 'backs up through sewers or drains' and water that 'overflows or discharges from a sump.' You need the water backup endorsement (sometimes called 'sump overflow' or 'sewer backup' coverage) to get protection.
How much does water backup coverage cost?
Typically $40–$100/year for $5,000–$25,000 in coverage. Higher limits ($50k+) cost more but are usually still under $200/year. It's one of the highest-ROI endorsements on a homeowners policy.
How much water backup coverage do I need?
Think about what's in your basement. A finished basement with HVAC, water heater, drywall, flooring, and stored belongings can easily hit $25k–$40k in damage from a single backup. If you have a finished basement, $25k is a reasonable floor; $50k is safer.
Is water backup the same as flood insurance?
No. Flood insurance covers surface water (rising rivers, storm surge, heavy rain) and requires a separate NFIP or private flood policy. Water backup covers water entering through your home's drainage system. Many basement floods are actually backups, not floods — and homeowners only learn the difference at claim time.
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Upload your declarations page. We'll tell you whether you have water backup, what limit you have, and whether it's appropriate for your basement.
Related reading
General information, not legal or financial advice. Coverage and limits vary by carrier and state.