Answer:

Depending on the circumstances, you may not even have to file a claim with your own insurer. Your neighbor's insurance may cover the damage to his or her unit. Or, the damage may be covered under a "master" insurance policy (owned by your condo association) that includes all of the individual condo units in the complex. But if these other insurance companies insist that you were negligent and should be held liable for the damage, you may need to turn to your own insurance.

As a condo owner, your homeowners insurance should protect you against property damage and liability (up to the limits of your policy) when someone is injured on your premises, or when you cause damage to someone else's property. So it's very likely that your insurance would cover at least a portion, if not all, of the other condo owner's loss (unless you deliberately caused your tub to overflow).

Before paying the claim, your insurance company may wait to see if the other condo owner receives any compensation from the master policy. In most cases, if the master policy covers a portion, or none, of the other condo owner's loss, your own insurance will pay the difference (again, up to your policy limits). If the master policy covers the full loss, your insurer may not have to pay anything.