Anonymous wrote:Condemned? Really?? The sewage should go back down the drain. Then bleach the floor. Is it carpet or tile?
There are probably roots blocking the pipes.
The safest thing to do is call a remediation company to clean up the basement for you.
If you are going to DIY, you should NOT clean up your basement with chlorox. It will not kill every contaminant that can be in sewage and it doesn't remove dead E. coli from the environment. Do NOT put fans on the basement; fans can blow contaminant all over the house. Remove everything from the basement and toss it. If the basement is finished, you need to strip it down to the concrete walls. All the wallboard, drywall, cabinets, flooring, etc. has to come out. You need to clean the remaining surfaces with some type of biocide. Make sure you wear gloves and HEPA masks when you are working with the stuff in the basement.
To prevent it from happening in the future: you need to check to make sure that your lateral line is intact. A plumbing company can do that with a camera. If the lateral line is intact, you need to have a check valve or back-flow valve installed so that sewage can only flow out, not it. You could also have a gate valve installed, if you want to be doubly safe. A gate valve is turned with a wheel. You may also need to install a sump pump.