For the most part, homeowners insurance offers a lot of coverage, but only when it comes to sudden accidents. Most policies will cover repairs if your pipes suddenly burst, if your neighbor's plumbing harmed your home, or if you had a sudden accident that caused a major plumbing failure in your house. The consensus is that you should expect your plumbing to be covered if it was a sudden failure that was not due to your negligence or active sabotage. So, things like plumbing breaks due to weather (with some exceptions) and defective parts are generally covered. If you have reason to believe that the damage you're seeing is due to a failure that had nothing to do with maintenance,
you probably have a good reason to call your insurance company and file a claim. With that said, how much coverage you get exactly depends on your plan.