Overhead sewer conversions are often expensive and not always possible depending on the layout of the upstairs plumbing and the configuration of the basement. Backwater valves are notorious for getting debris in their mechanism and allowing the sewage to enter anyway. A company in Chicago used to make a check valve that incorporated a pump that discharged any water that got through the check valve back into the city sewer. I do not know if they are still in business, but you could have your local plumber check to see if there are still units like that being produced.: : After a heavy rain, my basement toilet overflows. I get raw sewage all over the place. This happened for the first time in August and twice since then. Ive called the city (of Baltimore) and got no resolution. Last Thursday, when Hurricane Floyd passed through, I had 2 feet of the stuff in my basement.: : What can I do to prevent this problem and what are the ballpark costs?: I cant hazzard a guess about costs in your area,but will give a couple of thoughts.: -check valves(one way valves)are made for sewer lines. whether it would be practical to install one in main to your house or in the basement line would be a on site decision. : -another option would be capping off these lower level lines and installing a pump/tank for the basement plumbing that would discharge into upper level drain line. : such pump/tank for baths are made by many companies such as Zoller, Zurn,
