The better kind are normally open, and close with a float. They require a little drop typically from input to output. These are normally stainless steel or plastic.
Does Chicago have codes on this? I would be surprised if they did not You might ask in http://www.terrylove.com/forums/foru...Code-Questions
Your other alternative, which is more foolproof, is overhead sewers. Yes, it costs more. -- maybe $10000 to $14000 typically. A pit in the front yard can be good, and does not involve digging in your basement. Figure about $7000 to $8000. http://www.evereadyfloodcontrol.com/ (bad BBB) http://www.floodexperts.com/ (good BBB) Read the stuff on those sites as to how their valves worth. Those plastic valves from Canada look good too.
Don't try to book the work after a flood. Do it before.