My public sewer comapany is willing to install a backtrap valve to prevent the sewer from backing up into my basement, however, they want me to sign a release paper that will discharge them from any claims, demands damages actions and lawsuits arising out of the design, manufacture, sale, installation, use, maintenance and repair of such a device. I have several questions:
1) How reliable are they
2) How much does it cost to maintain them
3) Have they been around for long