By Paul Della · Licensed Insurance Agent · The Della Agency
An HO-3 is the homeowners policy most Long Islanders carry, and it covers a lot — fire, theft, wind, a tree through the roof. But living between the Great South Bay and the Sound means the perils most likely to hit your home are often the exact ones an HO-3 leaves out. Here's what your policy quietly excludes, why it matters here specifically, and how to close each gap before a storm finds it.
A standard HO-3 policy covers sudden, accidental damage to your Long Island home — fire, theft, wind, most water from burst pipes — but it does not cover flood, sewer or water backup, earth movement, or most mold, and wind claims are subject to a percentage hurricane deductible. On Long Island, flood and sewer backup are the gaps that bite most often, and a hurricane deductible can mean thousands out of pocket on a wind claim. The fix is straightforward: a separate NFIP flood policy, a water-backup endorsement, and a quick review of your deductible and limits with a licensed agent.
Most Long Island homeowners have an HO-3 policy and assume it covers whatever the weather throws at the house. And for a lot of what happens — a kitchen fire, a burst pipe, a break-in, a limb through the roof in a summer storm — it does. The trouble is geographic. When you live on a barrier-fringed island between the Atlantic, the Great South Bay, and the Long Island Sound, the perils most likely to reach your home are frequently the ones the standard policy was written to exclude.
This guide walks through exactly what an HO-3 leaves out, in plain terms, with Long Island's own exposures front and center: flood and storm surge on the South Shore, sewer backup into finished basements, bluff erosion on the North Shore, and the percentage hurricane deductible that quietly reshapes a wind claim. We're a licensed New York agency, and these are the gaps we'd much rather walk a homeowner through before a nor'easter than explain during a claim.
What Does an HO-3 Actually Cover on Long Island?
The short answer: an HO-3 covers your home against most sudden, accidental perils on an "open peril" basis — but "open peril" still comes with a fixed list of exclusions, and that list is where Long Island homeowners get caught.
The HO-3 "Special Form" is the most common homeowners policy in the country, and it's genuinely broad. Your dwelling is covered against any peril except those the policy specifically excludes, which means fire, wind, hail, theft, vandalism, falling objects, and sudden water discharge from plumbing are all typically covered. Your belongings are covered for a named list of perils, and you get liability protection and money for temporary living costs if the home becomes unlivable after a covered loss.
Here's the catch worth sitting with: "open peril" is not "all peril." Every HO-3 shares a standard set of exclusions — and on Long Island, several of them line up uncomfortably well with our actual risks. The table below is the quick version; the rest of this guide explains the ones that matter most here and how to close them.
| Peril | Standard HO-3? | Why it matters on LI |
|---|---|---|
| Fire, theft, wind, burst pipe | Covered | The everyday claims |
| Flood & storm surge | Excluded | South Shore & coastal zones |
| Sewer / water backup | Excluded* | Finished basements, high water table |
| Earth movement / erosion | Excluded | North Shore bluffs |
| Mold (beyond a sublimit) | Limited | Humid coastal climate |
| Wind during a hurricane | Covered* | Subject to % hurricane deductible |
*Backup is covered only with an endorsement; wind is covered but a percentage hurricane deductible applies. Both are explained below.
Why Isn't Flood Covered — and Why Is It the Biggest Gap on Long Island?
The short answer: no standard HO-3 covers flood anywhere, and on Long Island — with its barrier islands, South Shore bays, and extensive FEMA flood zones — that's the exclusion most likely to leave a homeowner with a catastrophic uninsured loss.
Flood is excluded from every standard homeowners policy in the country, full stop. That includes rising water, storm surge, and the kind of coastal inundation Long Island knows well. As the New York State Department of Financial Services spells out, flood losses aren't provided under standard homeowners policies; that coverage comes separately through the National Flood Insurance Program (NFIP) or a private flood insurer, and the majority of New York towns participate in the NFIP.
Why this hits Long Island so hard is simple geography. Large stretches of the South Shore — the barrier islands, the communities ringing the Great South Bay, low-lying areas from Long Beach through Freeport, Lindenhurst, Babylon, Bay Shore and out toward Mastic Beach — sit in FEMA-mapped Special Flood Hazard Areas. Superstorm Sandy in 2012 drove that home with billions in surge damage across exactly these neighborhoods. One more detail that trips people up: NFIP policies carry a standard 30-day waiting period before they take effect, so flood coverage is something to put in place well before hurricane season — not when a storm is already named.
How Do New York's Hurricane and Windstorm Deductibles Work?
The short answer: wind damage is covered by your HO-3, but during a hurricane it's subject to a percentage deductible — commonly 1% to 5% of your dwelling coverage — which can mean thousands out of pocket before the policy pays.
This is the gap that surprises people even when they technically have coverage. Wind is a covered peril, but coastal policies apply a separate hurricane or windstorm deductible calculated as a percentage of your home's insured value rather than a flat dollar amount. Per the New York DFS, these commonly run 1% to 5% of the dwelling limit. The state's own illustration: a home insured for $150,000 with a 5% hurricane deductible leaves the owner responsible for the first $7,500 of a hurricane loss. On a $500,000 Long Island home, that same 5% is $25,000 out of pocket.
The trigger matters as much as the number. Under New York's rules, a hurricane deductible generally applies only to wind damage occurring from 12 hours before a hurricane makes landfall in New York until 12 hours after the last hurricane warning is canceled — and only when the National Weather Service actually designates the storm a hurricane, not for an ordinary windstorm. Knowing whether your policy carries a percentage hurricane deductible, and how large it is, is one of the most important things to check before storm season.
A hurricane pushes surge across the South Shore and tears shingles off your roof. Say your home is insured for $500,000 with a 5% hurricane deductible. The wind damage to the roof is covered — but you pay the first $25,000 before the policy contributes. The flood water that ruined the first floor? Your HO-3 pays nothing toward it without a separate NFIP policy. Same storm, two very different outcomes, decided entirely by coverage you set up in advance. (Figures are illustrative — your deductible and limits determine the real numbers.)
Building coverage from scratch? Our guide to the best home insurance on Long Island covers what a strong policy looks like here — and how the right endorsements fit around your HO-3.
Does Your HO-3 Cover Water and Sewer Backup?
The short answer: no — damage from water or sewage backing up through your drains or a failed sump pump is excluded from a standard HO-3 unless you add a water-backup endorsement.
This is one of the most common and most frustrating Long Island claims, precisely because so many homeowners assume it's covered. When a heavy rain overwhelms an aging sewer main, or a sump pump quits during a storm, and water pushes up into a finished basement, a standard HO-3 treats that as excluded backup — not the covered "sudden pipe burst" people picture. The damage to flooring, drywall, furniture, and mechanicals in a finished lower level can run well into five figures.
Long Island is especially exposed here for two reasons: finished basements are everywhere, and much of the South Shore sits on a high water table with older sewer and septic infrastructure. The fix is inexpensive and specific — a water- and sewer-backup endorsement that adds a dedicated dollar limit for exactly this kind of loss. If you have anything of value below grade, it's one of the first add-ons worth asking about.
What About Earth Movement, Sinkholes, and the North Shore Bluffs?
The short answer: earth movement — earthquakes, landslides, and the gradual erosion or slumping of coastal bluffs — is excluded from a standard HO-3, which matters most for North Shore properties near the Sound.
Every HO-3 excludes "earth movement," a category that covers earthquakes, landslides, mudflow, and sinkholes. For most of Long Island that exclusion is quiet, but along the North Shore it isn't: the bluffs above Long Island Sound erode over time, and storms accelerate it. When a bluff slumps and takes part of a yard — or worse, threatens a foundation — a standard homeowners policy generally won't respond, because the cause is classified as earth movement or gradual erosion rather than a sudden covered peril.
This is a genuinely tricky area, and coverage options are limited and situation-specific. If you own a bluff-top or waterfront property on the North Shore, it's worth a direct conversation about what is and isn't insurable, and what risk you're carrying yourself — well before the ground starts moving.
Does Your HO-3 Cover Mold, Wear-and-Tear, and Old Wiring?
The short answer: mold is covered only in a limited way and usually capped by a small sublimit, and anything the policy views as wear-and-tear, neglect, or deferred maintenance is excluded outright.
Mold coverage is narrower than most homeowners expect. A standard HO-3 generally pays for mold only when it results from a sudden, covered water event — a burst pipe, for instance — and even then the payout is usually capped by a sublimit, often somewhere in the $1,000 to $10,000 range. Mold that grows from a slow leak, chronic humidity, or a problem you didn't address is treated as a maintenance issue and excluded. In Long Island's humid, coastal climate, that gap is easy to stumble into, and a mold endorsement can raise the sublimit if it concerns you.
The broader principle behind these exclusions is that homeowners insurance covers sudden and accidental losses, not the slow decline of a house. Damage from normal wear and tear, rot, pests, or long-deferred maintenance falls on the owner. For Long Island's older housing stock, that can also surface as trouble insuring a home with outdated wiring, an aging roof, or an old oil tank — issues better addressed proactively than discovered at claim time.
What Coverage Fills the Gaps an HO-3 Leaves?
The short answer: most HO-3 gaps close cleanly with a separate flood policy and a handful of endorsements — flood through the NFIP, water backup, mold, and ordinance-or-law for older homes.
The reassuring part is that almost every gap in this guide has a specific, affordable fix. You don't rewrite the HO-3; you layer the right pieces around it. The most important is flood coverage through the NFIP or a private flood insurer, especially anywhere near the South Shore or a mapped flood zone. From there, a water-backup endorsement protects a finished basement, a mold endorsement raises that sublimit, and ordinance-or-law coverage — which pays the extra cost of rebuilding to current codes — is well worth it for Long Island's many older homes.
| The HO-3 gap | How to close it |
|---|---|
| Flood & storm surge | Separate NFIP or private flood policy |
| Sewer / water backup | Water-backup endorsement |
| Limited mold coverage | Mold endorsement (higher sublimit) |
| Rebuilding to current codes | Ordinance-or-law coverage |
| Big hurricane deductible | Review the % and your limits |
None of this means over-insuring — it means matching your coverage to the way Long Island actually floods, storms, and ages. A quick policy review with a licensed agent is the cleanest way to see which of these gaps apply to your home and which endorsements are worth adding.
Once you know what's covered, the next question is how much it pays. Our guide to replacement cost vs. actual cash value for Long Island homes explains the setting that decides whether a covered claim rebuilds your house or just depreciates it.
The Bottom Line on HO-3 Gaps for Long Island Homeowners
An HO-3 is a strong, broad policy — but "open peril" isn't "every peril," and on Long Island the exclusions line up with our real risks in ways that catch people off guard. Flood is never covered. Sewer backup isn't covered without an endorsement. Earth movement and bluff erosion are out. Mold is capped. And even wind, which is covered, comes with a percentage hurricane deductible that can put thousands back on you.
The good news is that none of these gaps require a different policy — they require the right pieces layered around the one you have: NFIP flood coverage, a water-backup endorsement, ordinance-or-law for an older home, and a clear-eyed look at your hurricane deductible. If you're not sure which of these gaps your home actually has, our team will review your HO-3 for free and show you exactly where Long Island's weather could reach through it.
Frequently Asked Questions
No. A standard HO-3 homeowners policy never covers flood — including storm surge and rising water — anywhere, and on Long Island that's the single most important gap. Flood coverage comes from a separate policy through the National Flood Insurance Program (NFIP) or a private flood insurer. Given Long Island's extensive coastal and South Shore flood zones, most homeowners here need a flood policy in addition to their HO-3. Note the NFIP's standard 30-day waiting period, so you can't wait until a storm is in the forecast to buy it.
A hurricane or windstorm deductible is a percentage of your dwelling coverage — commonly 1% to 5% — that you pay out of pocket on a covered wind loss, instead of a flat dollar amount. Per the New York Department of Financial Services, a hurricane deductible generally applies only to wind damage from 12 hours before a hurricane makes landfall in New York until 12 hours after the last hurricane warning is canceled, and only when the National Weather Service designates the storm a hurricane. On a $500,000 home, a 5% deductible means $25,000 out of pocket before wind coverage pays.
Not under a standard HO-3. Damage from water or sewage backing up through drains or sump-pump failure is excluded unless you add a water-backup endorsement. This is a common and costly gap on Long Island, where finished basements and a high water table on the South Shore make backups a frequent claim. The endorsement is usually inexpensive and adds a specific dollar limit for backup damage — well worth reviewing if you have a finished lower level.
Only in a limited way. A standard HO-3 generally covers mold only when it results from a sudden, covered water event — like a burst pipe — and even then payouts are usually capped by a sublimit, often in the $1,000 to $10,000 range. Mold from long-term leaks, humidity, or poor maintenance is treated as a maintenance issue and excluded. A mold endorsement can raise the sublimit. Flood-related mold isn't covered by an HO-3 at all, since the underlying flood isn't covered.
A standard HO-3 excludes several major perils regardless of where you live: flood, earth movement (earthquake, landslide, sinkhole), water and sewer backup, damage from neglect or normal wear and tear, and losses tied to building-code upgrades (ordinance or law). Mold is limited to a small sublimit. On Long Island, the ones that bite most often are flood and sewer backup, plus the percentage hurricane deductible on wind claims. Most of these gaps can be closed with a separate policy or an endorsement.
Find the Gaps in Your HO-3 Before a Storm Does
Not sure whether you carry flood, water-backup, or how big your hurricane deductible is? Our team will review your Long Island homeowners policy, flag the gaps that matter here, and show you what closing them would cost. Free, no obligation.
✓ Last reviewed by the Della Agency team on . We refresh our guides quarterly — New York coverage rules, limits, and legislation change.
This guide is general information, not coverage or legal advice. HO-3 policy terms, exclusions, endorsements, and hurricane-deductible rules vary by policy and can change — read your own declarations page and policy, and confirm current requirements with your insurer and the New York State Department of Financial Services. Flood zones and NFIP terms are set by FEMA. Figures in examples are illustrative, not quotes.
Written and reviewed by the Della Agency team — licensed New York insurance professionals based at 1135 Deer Park Ave, North Babylon, serving homeowners across Long Island (Suffolk & Nassau) and 10+ states. Figures here are drawn from the named sources cited above — the New York State Department of Financial Services, the NFIP (FloodSmart), and the Insurance Information Institute — and reviewed quarterly. NY license #[insert].