I was down stairs in the basement doing some laundry the other day when I got this overwhelming smell of must. I went searching to find out where it was coming from. I found the source by the wall closest to the hot water heater. I went and looked how I would be able to fix this. I was looking online and I came across a dehumidifier. It seemed like that was going to be the easiest and cheapest way to get rid of the smell. I went the next day and bought one and it only took a few days for the smell to start to go away.