Homeowner Darin Ensing said that he was working around the house earlier in the day and had used a propane torch to splice a water line.
Ensing was not home at the time of the fire.
Around 4:50 p.m., Harry and Heidi Wojahn were walking down Fulton playing Pokemon Go when they noticed smoke coming from the second story of the home.
Wojahn said he knocked on the door and rang the doorbell. When he didn’t receive an answer, he called 911.
Grand Haven Public Safety Director Jeff Hawke said the fire could have started from a spark that got into a wall on the west side of the house.
Firefighters opened the wall in the area to check for possible extension.
The fire is still under investigation.