There are things that can happen to their homes that their homeowners insurance policies don't cover. Fire is the basic coverage provided by an insurance policy, while other common perils are water damage, theft, wind and liability. Earthquake and flood usually require a separate policy. In some states you can add earthquake coverage as an endorsement. It is important to discuss the risk you face and purchase the proper coverage. Just so you'll be forewarned, here are eight other perils, besides damage from an invading squirrel, for which you probably aren't insured.

1. Floods

Damage caused by flooding is excluded under standard homeowners insurance policies, according to the institute's primer on what disasters are covered by insurance. That's why it's prudent to obtain flood insurance, either from a private insurer or through the U.S. government's National Flood Insurance Program.

2. Earthquakes

When a 5.8 magnitude earthquake in Virginia shook the U.S. east coast in 2011, it caused as much as $300 million in losses and varying degrees of damage to 600 residences. Many of the owners may have been chagrined to discover that their homeowners insurance didn't cover the cost of repairing the harm to their houses. Coverage for earthquakes, which can damage foundations and collapse walls, requires a separate policy, though a standard homeowners policy generally will cover damage from fires caused by quakes, according to the institute.

3. Sewer Backups

Sewer backups can be pretty messy, and they're not covered either by homeowners insurance policies or flood coverage, according to the institute. Instead, you'll need to purchase additional sewer coverage.

4. Maintenance Damage

Maintenance damage. Homeowners policies don't cover damage caused to your home by your neglect of basic maintenance, according to the institute. Similarly, you're not covered if your house becomes infested by termites and other pests, or develops mold.

5. Backyard Trampolines and Pools

Sure, they're fun. But according to the National Association of Insurance Commissioners, both trampolines and pools are dangerous enough that some companies may not insure your property if you have them, or else may exclude liability for any injuries related to them. They also may even cancel your policy if you don't inform them when you get a trampoline or a pool, or don't follow the policy's safety guidelines.

6. Dog Attacks

If your family pet bites a visitor, you're typically covered for legal liability up to your policy's liability limit — usually $100,000 — according to the institute. The average dog bite claim is around $39,000, so you should be OK. But it's a bigger problem if you own a breed with a reputation for being aggressive, because some insurance companies won't cover you at all.

7. Really Expensive Jewelry

Typically, homeowners' policies set a limit on how much bling they'll cover — usually around $1,500, according to the institute's article on jewelry and other valuables. If you've got a lot of costly rings or necklaces, you'll want to consider getting a floater policy, which covers any sort of loss, including dropping your ring down a drain. That'll require you to get the items appraised professionally.

8. Your Stuff in Someone Else's Basement

If you've got a friend or neighbor who allows you to store some of your possessions in his or her basement, you could lose out in the event of a disaster, according to Amy Bach, executive director of United Policyholders, a California-based consumer advocacy group. That person's insurer isn't going to cover your losses, since you're not the homeowner. "You'd have to try to collect money from your friend," Bach says.