There's a decades-old plume of TCE and PCE in Chico, CA that migrated nearly two-miles from its source and has contaminated residents' well water for years:

The Skyway plume was discovered when area residents asked for wells to be tested because they were concerned a nearby tank farm might be leaking petroleum-based contaminants into their groundwater. Instead, unacceptable levels of chlorinated solvents were found and traced back to an operation that manufactured aluminum shower enclosures on Speedway Avenue from 1962 until 1976.

Preliminary tests revealed the contamination extends about two miles from its origin, flowing under Skyway and Cessna avenues and ending along Hegan Avenue near the Chico State University farm. [see map]

Just this week, ABB, the company being "held responsible for clean-up costs," agreed to pay for 63 residential hook-ups to the water system run by California Water Service Company (a.k.a. Cal Water). Meanwhile, the investigation into the overall size of the plume continues.