"It's a ticking time bomb," said builder Paul Maina.
Maina is warning flood victims about what may happening beneath their floors. He showed Action News a charred electric wire he found only after pulling up the subflooring at one of the homes he's fixing.
"We would see these kind of spark and smoke, and we'd run over and shut off all the breakers," he said. "Would you feel safe living in your house knowing that this was underneath your home?"
Almost six months after the storm, Maina says the insulation in some electric wire is still soaking wet. The concern is that flooding has compromised wiring, junction boxes and any other connections that were underwater during the storm.
"Any exposed wire itself that does get wet, the salt water just corrodes it," said electrician Craig Wharton. "And you could cause your house to short and it will eventually spark a flame."
Linda and Ed Reilly of Beach Haven took the threat seriously after their contractor warned them.
"Had almost three feet of water in the living room, so everything all the way down to the crawlspace had to be changed," he said.
The Ocean County Fire Marshal's office says at least 20 fires since Sandy can be attributed to wiring that was damaged by the storm.
It's not clear if that was the cause of a blaze on 80th Street in Beach Haven early Saturday morning. Fire officials say the home was damaged too badly to tell.
But firefighters are urging homeowners who did get water to have an electrician check everything out, including wiring UNDER the house.
"They come down, they flip that power switch," said Shipbottom firefighter Rob Roth, "and if that outlet has been decimated by the salt, it's going to cause a fire."
The fire marshal says even if things look okay to the eye, if you've had water under or in your house, you need to get the wiring replaced or you are really tempting fate.