I recently had some landscaping done (added about 1-3 feet of dirt) and one of the workers broke off my sewer cleanout cover with a Bobcat. I replaced the cap, but a week later it had popped off due to a backup in the line (littering my backyard with sewage). A plumber came out to look and we could see a Gatorade bottle about 7 feet below the next cleanout access point (it apparently fell in after the workman used it to mark the spot). The plumber could not force it out with a snake and said he'd need to dig and remove that section of the pipe. He was also concerned about trying to force it since he said the city line didn't begin until about 15 feet later near the manhole.

Before committing, the landscaper (who agreed to pay) requested I try Roto Rooter who may be able to force it out or dig it up for less $$. When they came, the said they could see a tree root in the same place as the bottle and that the root was not letting the bottle through (because that's when the 6 inch pipe should have started, contrary to what the other plumber told me). They were able to move the bottle through the line, so that problem is gone (I hope?), but I'm worried about roots now. Incidentally I could not see the roots, and the other plumber didn't mention anything. He used root remover chemical and estimated I had about 8 months before another backup happens (can he really tell that based on such limited info???)

I've never had plumbing problems until this incident (house is 5 years old) so was this coincidence or an accident waiting to happen? Can the naked eye see roots from that distance just using a dim flashlight? Does Roto Rooter prey on people's insecurities about this? Or am I just not wanting to believe it? Any advice is appreciated, about any part of the above.

Thanks.