I found this article on the ABPA website. It touches on the issue of liability and who ends up paying in the end. Liability is an issue I take very seriously. We in the backflow prevention industry do not discuss liability nearly enough, in fact some times it is actually a hushed subject. Our province and its water purveyors have many opinions with respect to how backflow should be dealt with, including the liability.  The ABPA link for this article is,

http://www.abpa.org/bb/viewtopic.php?p=1197&sid=361db3f49abd3cd35a7593ad8a7e97e7

Plumber quit after tainting water

After a company twice contaminated the water system at Normandale Community College last year, its owner can no longer do plumbing work in Minnesota, the state Department of Labor and Industry said last month.

Employees of Mechanical Solutions, Inc., a St. Paul company owned by Richard Ellingsworth Jr., were working on a cooling tower at the Bloomington college in June 2009. They attached a hose without using a backflow preventer, allowing ethylene glycol into the drinking water system. Seventeen days later, company workers let chemicals backflow into a water heater. No one got sick. Both times the system was flushed.

A $25,000 fine against Ellingsworth was vacated after the department was told the business had been closed.