We have an ISO form policy. HO 00 03 04-91, special form. The town our insured is in sustained heavy wet snows totaling about 16". This snow load caused numerous power outages. The power to the waste treatment plant was out. This caused the pumps to stop working thus causing the sewage to backup into our insured's home. There was no damage to the insured's home from the snow, only the backup of sewage in the basement. They do NOT have the sewer backup endorsement. Is the peril a Power Surge, Weight of Snow or Backup of Sewage? Is there coverage for the interior damage to the insured's home?

Montana Subscriber

 Neither power surge nor weight of ice or snow would apply in this instance. Weight of ice or snow must occur on premises, and power failure is excluded when it occurs off premises. This is a sewer backup, and even if another covered peril was at play, the exclusion section is preceded by the anticoncurrent causation language, so even then the damage from the sewer backup would not be covered.