Not necessarily. While having a pool is considered an "attractive nuisance", because it can pose a danger to unattended children, the additional risk does not necessarily cause a huge jump in premium. Something to consider, however, is the replacement cost coverage on your policy. If you are adding an expensive pool to your back yard that causes the replacement cost of your home to significantly increase, you may see an increase in your homeowners insurance
premium. Your best bet would be to contact a pool builder for an estimate and then contact your homeowners insurance agent to ask how that would impact your policy specifically. And it may be a good idea to ask about additional liability coverage for more protection.