NEW YORK (CNNMoney.com) -- A large percentage of homeowners are in the dark about their insurance policies, according to a new study by the National Association of Insurance Commissioners (NAIC). Here are a few common misperceptions about coverage:

About 33 percent of policy holders still think flood damage is covered by a standard homeowners or property and liability policy, according to the study. To get flood insurance you need to get it through the government. Here's your first move: Go to floodsmart.gov. You'll be able to gauge your risk of flood and get price estimates for your home. If you live in a flood zone, you don't want to be without this coverage.

34 percent of homeowners think mold damage is covered. But mold, like rot and termite infestation, is generally not covered by a homeowners insurance policy. There is no separate mold policy you can buy. But there are steps you can do to minimize your risk. Keep the humidity level in your home between 30 percent and 60 percent by using air conditioners or dehumidifiers. Put exhaust fans in kitchens and bathrooms. And don't install carpets in damp areas such as basements or bathrooms.

37 percent of homeowners think damages from a sewer line break on their property that connects to their sewer system are covered. But homeowners are responsible for the maintenance and repair of their house and the pipeline between the city sanitary sewer main, usually located under the street, and the building.

The cost for coverage is about $50 a month according to the Insurance Information Institute. Water-starved tree roots may be a big factor in sewer blockage. These tree roots make their way into sewer line cracks and grow over time. So, if you have a lot of trees in your area, you may want to investigate these policies.

Just like flooding, Earthquake coverage is not covered under a standard homeowners policy. You can get coverage from private insurance companies. Deductibles can range anywhere from 2 percent to 20 percent of the replacement value of the structure. In California, homeowners can also get coverage from the California Earthquake Authority (CEA), a privately funded, publicly managed organization.

We just want to mention one more misconception: the difference between actual cash value and replacement cost. 12 percent of people surveyed didn't know which kind of coverage they had. Remember, actual cash value is the amount it would take to repair or replace damage to a home and its contents AFTER depreciation.

Replacement cost is the amount it would take to replace or rebuild a home or repair damages without deducting for depreciation. An actual cash value payout could be thousands of dollars lower than a benefit calculated at the replacement cost according to the NAIC.

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By Gerri Willis, CNN