Oil tanks that can cause serious environmental contamination are buried in the yards of older homes across Metro Vancouver, but as one North Shore woman learned, removing them can cost hundreds of thousands of dollars.

The City of Vancouver requires that homeowners should remove the tanks if they're not in use, and other municipalities strongly recommend it. West Vancouver Asst. Fire Chief Martin Ernst told CTV News that the tanks will start to corrode after about 15 years underground.

"Ultimately, it can spill its contents into the environment," he said.

Ernst estimates that about 1,000 tanks have already been removed from West Vancouver lawns, but 2,000 or 3,000 remain.

Susan Aldred discovered one in her yard when she tried to sell her home in 2008; she says the previous owner had given her the impression it had been taken care of.

"I had no idea there was an oil tank -- there was no signs of an oil tank," she said.

The law requires homeowners to disclose the presence of oil tanks when their sell their homes.

Contractors from the company Digger Dicks removed the tank and told her that the soil throughout the yard was contaminated. The remediation work "destroyed" the property, Aldred said.

The bill for the work started at $3,500, but only grew from there.

"Digger Dick then put a lien on my property and he wanted $224,000 for removing the oil tank," Aldred said.

Richard Lambert, the owner of Digger Dicks, said he wasn't trying to rip off Aldred.

"Hers was a nightmare job," he said.

Digger Dicks agreed to a lower bill in a court settlement. Aldred sued Lynn and Al Colbeck, the previous owners of the home, and a judge ruled that they had to pay for the environmental cleanup.

Jim Sullivan, the lawyer for the Colbecks, told CTV News the couple was disappointed by the ruling.

"They felt they had taken all appropriate steps," he said.

In a statement, the Colbecks said, "We find it disturbing that individuals such as ourselves ... can still be subject to liability years later."

After the soil contamination mess, the deal to sell Aldred's home fell through and she ended up selling for a lot less. Nearly three years later, she's still waging costly battles in court.

"Financially, we've lost well over a million dollars. It's been devastating," Aldred said.

She says she can no longer afford to live in her current home and is selling it.

For more on contamination from oil storage tanks, see the B.C. Ministry of Environment fact sheet.

Watch CTV News at Six for a full report from Mi-Jung Lee

Watch CTV News at Six on Tuesday, March 22 to learn why disputes over buried oil tanks could become more common