Montgomery County police identified the victims on Sunday as 29-year-old Crystal Puderbaugh and 4-year-old Lily Puderbaugh.
They were found unresponsive outside their home on Saturday afternoon. Police say a portable sump pump was found in standing water nearby. Police believe the water was charged and an electrical surge led to their deaths.
Police say autopsies revealed that Crystal Puderbaugh died of drowning and electrocution. For the girl, electrocution was the sole cause of death.
There was flooding in the area at the time after heavy rains throughout the day. Police say no foul play is suspected.