Sewer Cleaning – Keep Roots from Becoming Pipe Blockage

Most cases of sewer cleaning involve tree root removal. So, chance has it that if you are experiencing a sewer line backup, roots are most likely the cause.
How do Tree Roots Block Up My Sewer Pipes? How Do They Enter?
Ever see grass growing through the cracks in the sidewalk? The grass does not break the concrete with its sheer will to see the sun. Instead, the changing temperatures of the seasons expand and contract the sidewalk until it breaks under the strain. It is only after that point, when there are tiny holes in the concrete, that grass seeds that have lain dormant for years begin to sprout up through the cracks.
The same principle is true of tree roots and sewer pipes. As trees grow, their roots continue to expand throughout the surrounding topsoil, in search of water and nutrients to sustain the growing tree. The roots naturally grow in the direction of the most sustenance; that is how they provide the most value to the tree. In application to sewers, this is both bad news and good news.
The good news – tree roots will not be attracted to water-tight sewer pipes (there will be no sustenance around the pipes to take the roots' interest
The bad news – tree roots will be attracted to sewer lines that already have cracks in them (roots are drawn to increasing amounts of water, beginning around the sewer line and ending in the sewer line itself)
Over the Soil and Through the Cracks...
So, roots will enter through the cracks in the pipeline and begin to spread through the drain. Once they are thick enough to keep detritus from passing through, they will cause a sewer line backup. This means that if you have noticed a slight backup, acting quickly will be necessary, as the roots will only continue to grow, and waste material will only continue to build up.
What a Homeowner Can Do
Once a pipe blockage is detected, there are a number of different options one may choose from.
Chemicals are available for use on the pipeline directly, which are merely flushed through toilets. These chemicals are toxic to tree roots and our environment, killing all they come into contact with. While these chemicals can work for a time, they often will kill only the roots that hang down into the sewer water, leaving the rest to grow back. For this reason, these chemicals are best used as a temporary treatment.
Clean them yourself by following the step-by-step instructions found on web sites, such as Ask the Builder and Drains and Plumbing. 
Ask a professional to help you determine the best course of action.