Inquiring minds want to know......

What was the fix?

Pipe by the clean out was backing up. They cleaned the line and all is good now. They did not find any roots though. I am going to get som rock salt and pout down for root prevention.

Waste of time putting rock salt in a line for roots. It will only get pushed down the line, everytime water is used in your house

Explain the term, "Pipe by the Clean Out was backing up", Are you talking about a lateral line?

They ran the line from the clean out to the street. I was not outside when they did it.

I'll bet the house was vacant for a while.....

I believe the house was vacant for 6-8 months.

Kinda harsh punishment there Dave

http://www.wptz.com/news/21336430/detail.html

I hate to wake up to a clogged toilet.

Quite Common.

If the house was new, I have seen the Closet Bend (The hole in the floor the toilet sits on), be used as a trash can and debris is ran down the line (Nails / Grout / Small pieces of trimmed tile) and it can cause back ups.

If it happens again, have you homebuilder run a camera down the line and make sure the line is clear from debris

After owning a few rentals, I've seen it all! Here's what happens......when the house is occupied, water goes through the drains on a regular basis....the roots in the ground get fed from the little bit of water that seeps through the joints in the sewer pipes. When the house is vacant, the roots seek the water, and creep into the tiny crevices in the sewer pipes, thus clogging the main sewer.
One of the first things I used to do was buy a gallon of Muratic Acid, and pour it down the main cleanout, perferably, when nobody is going to use the water, like overnight.
Using Muritic Acid has saved me many times. The only thong is not to use it regularly...it's corrosive and not good for your sewer pipes if used too often, about once or twice a year. The other thing is even the smallest drop will burn a hole right through your clothes, I ruined many pairs of levis! Muratic Acid is used by masons for cleaning bricks, they dilute it though. It's about $5.00 bucks a gallon. I've seen the stuff work.....
RC Fishing World

They also use it in swimmming pools. I used to use Muriatic Acid to intentionally "age"(rust) hinges and bought mine in the 5 gallon bucket size at a place that sold swimming pool supplies.

Go to a plumbing supply and find a product called "Thrift" use it monthly and never again will yoy have problems unless someone flushes their shorts down the pot. Thrift even keeps the hair out of the bathroom sinks where folks wash their hair.

How much epsom salt and how often?

Copper sulfate kills roots in lines. You can find it at Lowes Home Depot.