I have something blocking part of my main drain line in the my house. If I run several things at once such as dishwasher and washing machine or a couple of showers at once, the showers get water coming back up into them. It doesn't happen very fast and the water drains out eventually. Is there anything that I can do before calling a plumber? I haven't used a pipe snake before. Some people where I work have said to put muriatic acid down the drain but I have read not to do that on several forums and haven't found an online source that says it is ok to do so.