When we flush the toilet it causes a flow up into the standing shower next to it.

We have a separated bath room that works fine so do not believe it is the septic tank.

Would a liquid drain cleaner help or must we remove the toilet and run a snake down the line to unclogg it?

Thanks,
Wayne Everett

You have a drain line clogged. Do you have two septic systems, if not I think the clog is before it gets to the septic tank or the other bathroom would not work properly. Run a snake down the vent pipe up on the roof, the large one behind the commode that is stopped up/.