I'm planning to replace my asphalt driveway and wooden front entrance walkway with concrete. But before I do that, I'd like to check the condition of my sewer clean-out to make sure that the many trees I had in the front yard didn't affect the sewer line leading to the street with their roots. I'd hate to have to dig up the new driveway and walkway. The problem is, I cannot find the opening for the clean-out. By the way, my house is a 35 year old 1 story ranch, built on a slab. There is a 4" PVC pipe sticking out a few inches above the ground just a few feet from the front of the house with a cap on it. I thought this was the clean-out. After investigation, I found that two feet under the opening, there is a valve, left in the open position that requires a special tool. I'm guessing it's the main water shut-off to the house. There is also a meter and shut-off located in the easement about 30' away, right before the street. My neighbor had a problem with water backflow and hired a plumber. The plumber could not find the clean-out and had to dig up the front yard to find the line leading to the street. It turns out that the line was being blocked by roots and there never was a clean-out. My neighbor had the plumber install one. I went to City Hall to get a blue print, hoping it would help, but unfortunately, they only keep them for ten years.
Is this a valid concern?
Should I worry about the sewer line before the contractor pours the concrete?
How can I find out the location of the sewer clean-out or if I even have one?
Would the municipal utilities authority have a map or lay-out plan that could help?

Many homes 30 years ago did not have a clean out installed, it was very common back them for the plumber to take the manual snake and remove the toilet and snake from there, or go to the roof and snake though the vent pipe.

I would seriously advice adding a clean out to your sewer. But for an inspection, you should be able to hire a inspection company to run the camera though the vent pipe.

Thank You Chuck,
I went to the water company today and the rep confirmed that my house does not have a clean out. To find where the line is, he recommended using the vent pipe as a guide. I'm going to contact a professional for proper inspection. Eventually, I will have a clean out installed.
Thanks again for your answer.

You do know when the... +++ is flowing back into the bath tub and on the floor is not the best eventually time. They are fairly cheap to have one put in, they can merely locate the line coming out of the house, dig down to it, tap into it, and bring a line up to ground level.

I had one added to mine home this year, I waited to it was too eventually myself. Cost under 200. And I could have done it myself for a lot less. ( back not up to digging like it used to be)