Glossary

HO-1 (basic form)

The oldest and narrowest ISO homeowners policy, insuring a short list of named perils; it has been largely discontinued.

Also called: HO 00 01, HO1, basic form

HO-1 is the original basic form in the ISO homeowners family. It insures the dwelling, other structures and personal property against a short list of named perils, about 10 in all: fire or lightning, windstorm or hail, explosion, riot or civil commotion, aircraft, vehicles, smoke, vandalism or malicious mischief, theft, and volcanic eruption. Liability and medical payments coverage are included. Anything not on the list is not covered, however sudden it is.

That list is the weakness. A pipe that freezes and bursts, a roof that collapses under heavy snow, or a power surge that ruins a furnace all fall outside it, because those causes were first added in the broad form, HO-2.

Most insurers no longer offer HO-1, and it has been dropped in nearly all states as buyers moved to broader coverage. If a quote or an old policy turns out to be on a basic form, compare it with an HO-3 before renewing, and read named perils vs open perils coverage to see what the difference means in a claim. The full family is laid out in Homeowners policy types: HO-1 through HO-8 explained.

Last reviewed October 10, 2026

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Related terms

HO-2 (broad form) A named-perils homeowners policy covering 16 listed causes of loss for the house and belongings: broader than the basic form, narrower than the special form. HO-3 (special form) The most common homeowners policy: open-perils coverage for the house and other structures, and named-perils coverage for belongings. Named perils Coverage that applies only to the causes of loss listed in the policy, so a claim is paid only if the damage came from one of them. Open perils Coverage that applies to any direct physical loss unless the policy specifically excludes the cause, so the insurer must point to an exclusion to deny a claim. DP-1 (basic dwelling form) The basic dwelling form: it covers a short list of named perils to the building, typically at actual cash value, with no liability coverage built in.

Related guides

HO-2 broad form vs HO-3: what changes in a claim The HO-2 insures the house against 16 named perils; the HO-3 against anything not excluded. Where the gap shows up, who must prove what, and lender limits.