Image: Dog © Alley Cat Productions, Brand X, Corbis

Related topics: insurance, home insurance, insurance claims, homeowners insurance, insurance rates

Insurance broker Doug Akiyoshi once walked into a backyard in Seattle to take some pictures of a potential client's house.

"Suddenly, this dog appeared out of nowhere," he said. "It was a Lab, and it was in attack mode. And I climbed that wall as fast as you can imagine."

Akiyoshi, based in Mercer Island, Wash., said he later phoned the owners and told them: "You know, you've got a problem here. Does that dog have a biting habit?"

"And they said, 'Well, that was one reason why we got dropped by our other carrier,'" Akiyoshi recounted.

He informed them that the dog was why he, too, would be declining coverage.

Homeowners often learn the hard way that standard insurance policies don't cover natural disasters such as floods and earthquakes. But less dramatic -- and less well-known -- problems can put even a standard policy out of reach.

Dog bites, for example, account for one-third of homeowners' liability claims, costing insurers $412 million in 2009. As a result, agencies have all but blacklisted homeowners with pit bulls, Rottweilers and other dogs included on the U.S. Centers for Disease Control and Prevention's list of deadly breeds. But a dog of any breed with a history of biting -- such as the dog belonging to Akiyoshi's would-be clients -- is likely to send insurers running.

Knob and tube? Time to rewire

Knob-and-tube wiring was the main method of electrical wiring from the 1880s through the 1930s, lasting even into the 1950s. Back then, a single outlet per room was common, and the average household's few appliances didn't collectively suck much power.

What concerns insurers is the strain that today's power-hungry appliances place on older wiring. Knob-and-tube wiring typically doesn't have a ground, and you're not supposed to use modern three-hole outlets unless the ground is functional.

Fuse boxes, which often accompanied older wiring, pose another problem. As a safety feature, the fuses have thin slivers of metal designed to "blow" when too much electricity courses through them, shutting off power. But homeowners occasionally try to beat the system and keep the electricity flowing by sticking pennies, which are much thicker, into the fuse sockets. Doing so makes the wiring inside a house's walls hot -- so hot that the house could catch fire.

Good luck convincing an insurance agent that you would never try this.

Some regular carriers will cover you without making you tear out all your knob-and-tube wiring. They can live with it running between a wall switch and overhead lights, assuming you've otherwise rewired with grounded outlets for power-hungry appliances such as microwave ovens, TVs and hair dryers.

The bad news: Paying for those upgrades, plus a new circuit breaker, costs thousands of dollars. So "affordable" insurance doesn't necessarily come cheap.

Bottom line: Most carriers consider extensive knob-and-tube wiring a fire hazard and won't insure a house that has it.

Past claims or a dropped policy can doom you

Let's say you've been living in a condo when you get a job across the country, somewhere you can afford to buy a house. You cancel your condo homeowners policy and move into an apartment until you can occupy your single-family residence.

But 18 months ago, while still in the condo, you filed a water-damage claim under your homeowners policy -- a claim easily accessible to all carriers through a shared database.

You can pretty much cue up "game over." Filing any claim can be the kiss of death when your policy comes up for renewal. But you're even more likely to be a dead duck if you let your insurance lapse.

That's because carriers hold new clients to even tougher standards. And by letting your policy lapse, that's what you've become.