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While we now know power lines started the deadliest wildfire in California history, a different type of threat is affecting plans to rebuild: danger in the water system. Melted metal, plastic and wood created a toxic mix that officials say, six months later, has contaminated the town of Paradise's water pipes. They've tested positive for elevated levels of cancer-causing benzene, reports CBS News correspondent Jonathan Vigliotti.

"If my kids get cancer in 20 years, I'll never forgive myself," Paradise homeowner Jessica Distefano said. When she and her family moved into their dream home last summer, they never imagined this would be their reality.

The Camp Fire killed at least 85 people in and around the town of Paradise last November. Twenty-seven thousand people once lived there, but only 1,500 have returned. Nineteen-thousand buildings were reduced to ash in the Camp Fire.

The irrigation district said the pipes were contaminated either by melted water meters or toxic air from the fire that was sucked into the system.

"We've tested about 500 service lines in our district at this point and about 30 percent of them have come up with contamination," Paradise Irrigation District manager Kevin Phillips said.

Phillips and his team are testing the water along 173 miles of pipeline to find out which sections need to be replaced. That alone could take two years. For now, the water is unusable.

"The process we're facing is monumental. It's something that there's no game plan that's been written for it," Phillips said.

"It's definitely been difficult to have a standing home in Paradise right now," Distefano said. "At times we wish that it was gone."

Massive water tanks are their lifeline for cooking and bathing. For the basic need, Distefano said it costs her family about $250 every three to four weeks.

Their insurance company, Farmers, said it will soon stop reimbursing them for those fill-ups.

"They said we'll get one more refill and then they're done, and I said, but it's contaminated. He said that's not in our policy," Distefano said.

Jessie and Martin Thompson, whose home was the only one on their street that survived the fire, also rely on their water tank.

"We tell our girls no more baths. Try to do two-minute showers," Jessie said. "We don't want to take chances with our babies… For us, it was really big peace of mind. We just wanted some security."

Securing safe water is also key for Paradise businesses and schools that hope to eventually re-open. There were about 1,200 businesses in town before the fire. So far, about 10 percent have re-opened including two coffee shops and one restaurant.

"We are an essential service, an essential part of the town to rebuild and we take that very seriously," Phillips said.

While the crews cleaning up around town are a welcome sign, homeowners know fixing the water system is crucial to rebuilding their community.

"If we can't have clean water, then we can't have a town," Jessie said.

"We'll wait as long as it takes," Martin added.

"We have to look at what has tore this town apart but then we have to look on the positive side," Jessie said. "We're working on our comeback story."

We reached out to Farmer's Insurance Group, and the company said the additional payments for the water fall outside of the family's coverage limitations.