Glossary

Surface water

Rain or melted snow that spreads across the ground without a defined channel, treated as flood damage and excluded from homeowners policies.

Also called: overland water, runoff, diffused surface water

Surface water is water from rain or melting snow that spreads over the ground without following a defined stream or channel, until it soaks in, evaporates or reaches a watercourse. The ISO homeowners form lists it in the flood exclusion, so a homeowners policy generally will not pay when it enters your house.

Where the water was when it got in decides the claim. Rain that comes through a hole in the roof opened by wind or hail is one peril. Rain that runs down a slope, collects against the foundation and enters at a basement window well or garage door is surface water. Say a thunderstorm drops three inches of rain in an hour, the street drain backs up and water pools into your low entry (hypothetical). Expect the homeowners insurer to deny that loss as surface water or flood.

Flood policies are written for this. The National Flood Insurance Program (National Flood Insurance Program) defines a flood as a general and temporary condition affecting two or more acres or two or more properties, and its definition includes unusual and rapid accumulation or runoff of surface waters from any source. You do not need to be near a river or in a mapped zone for surface water to reach you. The guide do you need flood insurance outside a high-risk zone? explains who should still consider flood coverage.

Last reviewed October 10, 2026

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Related terms

Flood exclusion The standard homeowners provision that excludes flood, surface water, tides and overflowing water bodies, leaving flood damage to a separate flood policy. Water damage exclusion Policy language that excludes certain kinds of water loss, either the standard flood, backup and groundwater group or a broader endorsement an insurer adds. Storm surge The abnormal rise of seawater that a hurricane or strong storm pushes onshore above the normal tide, treated as flood and excluded from homeowners policies. Water backup coverage An optional add-on that pays for damage when water or sewage comes up through drains or sewers, or when a sump pump fails or overflows. National Flood Insurance Program (NFIP) The federal program, run by FEMA since 1968, that makes flood insurance available to owners and renters in communities that adopt floodplain management rules. Flood zone A map designation, such as Zone AE, VE or X, that classifies a property's flood risk and helps decide whether a lender will require flood insurance.

Related guides

What flood insurance covers in a basement NFIP flood insurance covers only a short list of basement items, like the furnace, sump pump and unfinished drywall. What is excluded and how to fill the gaps. Does homeowners insurance cover flooding? No. A standard homeowners policy excludes flood, surface water and storm surge. Flood coverage takes a separate NFIP or private flood policy. Is water damage covered by homeowners insurance? Sudden water from a burst pipe or failed appliance is usually covered; flood, sewer backup, sump overflow and slow leaks usually are not. How to tell which. Sump pump failure and basement flooding Sump pump failure, groundwater and surface water are excluded from a standard homeowners policy. What an endorsement or flood policy adds to a basement.