You don't. To raise the liability on your homeowners policy from 100k to 300k is about $8 a year. Most people get extra liability insurance in the form of an umbrella policy for exposures like pools and trampolines. An umbrella varies in cost based on all your underlying exposures (house, boat, car, atv, etc) but for the typical situtation, a 1 million dollar umbrella should run somewhere between $100-$200 a year.
I didn't change my insurance. But I did buy and install the cage thing that goes around it to keep people from falling off. That thing has saved countless lives. I highly recommend it.
I was going to change my insurance company to Geico but they told me they don't offer any discount homeowner's insurance if you have a trampoline. Too much of a liability they said. They won't write a new policy if you own one.
Geico insures our cars. They offer a discount on homeowners insurance through a "partner" company. I called to get a quote and they told me they couldn't insure me if I own a trampoline. I do have the enclosure too.
We have 2 trampolines. No extra for insurance. My one has never had an enclosure on it and we did that on purpose. We found that ours tended to be more daring w/ the enclosures at friends' houses & such. No one has ever fallen or broken a limb w/out the enclosure at this house. Now, we recently picked up another one. It comes w/ an enclosure and still debating whether to put it up or nto. Leaning towards no as the other goes so well w/out it up. We are strict though w/ the rules of it. Remember, there were NO enclosures for these things when we were growing up--LOL. I know, I know, OSHA would probably have a fit at this house--LOL. But, never heard of the insurance being an issue before. We're insured w/ no problems. Stephanie--mom to 7