Ok, I awoke to a nasty situation in my downstairs bathroom. It looked like there was an explosion from the toilet and there was "stuff" all over the place. Luckily it wasn't gallons of it that had to be wet vacuumed up, but it was a pain to get cleaned up.

The toilet flushes just fine now, so do the 2 toilets on the 2nd floor. The tubs and sink drain just fine as well. We had a lot of rain last night, if that matters. I am at a lost as to what in the heck happened. This has never happened before in the almost 9years I have been in the house.

I did a little investigating and found out about a backflow (backwater?) valve that could possibly have prevented it. I'm just worried that it will happen again. I have a call into a plumber to have my system looked at, but I wanted to gather info.

What's going on? Thanks.

Call the city and ask if they have been flushing the sewer lines, sounds like your back flower preventer did not stop the city pressure during cleaning.

Ask the plumber to check and see if your rainwater runoff is connected to your sewer and let me know. Tom

Call the city and ask if they have been flushing the sewer lines, sounds like your back flower preventer did not stop the city pressure during cleaning.

Thanks for such a quick response! I will call first thing in the AM to find out. Now, is the backflow preventer the same thing as a backwater valve?

Yes

Yes,
And here's what one looks like,(see image)