The sewer service line from your house generally does not fail at once. The condition that ultimately leads to a problem occurs over a long period of time. Deterioration of sewer pipe includes settling that create sags that can trap solid materials, cracking of the pipe itself and pipe joints that begin to leak. Tree roots can get into the pipe through the cracks and joints creating obstructions. The roots will also create stresses on the pipe further deteriorating it.
Groundwater will enter through the cracks and joints and over time more and more groundwater will enter as the pipe continues to deteriorate. This groundwater which increases when it rains could overload the entire sanitary sewer system resulting in sewer backups. Clay pipe which was commonly used before the mid1980s is more susceptible to cracking and deterioration. More frequent cleaning and repairs to the sewer lines are needed the older the house and its sewer lines become.
Will the repair that is being proposed eliminate the cause of the problem or does it only address the effects of the problem? As an example, if root intrusion is causing a backup, the possible solutions will range from rodding (partial opening up of the lateral to restore some drainage), to root cutting (cutting of the roots from the full diameter of the pipe). In both cases the roots will eventually grow back. To eliminate root intrusion altogether the sewer service line would need to be replaced or lined. Each option has a different cost with different long-term effects.
Service Line Reach
How far up the service line will contractor rod or rootcut? There may be several spots where there are partial obstructions. The closest one may be opened up only to have another blockage in the near future. It is always best to have the entire service line cleaned to the sewer main. Some contractors may be reluctant to go all the way to the main for fear of getting their rodder or cutter stuck. Find out how far he actually went.
Occasionally the blockage cannot be cleared by rodding or root cutting and the service line must be dug up and a section of pipe replaced. If the service line is in bad shape, then replacement or lining may be necessary. These types of repairs need a permit from the village.
Older homes were generally built without outside cleanouts. The only access to the sewer line might be in the basement. As a result getting the rodder or cutter into the service line may be difficult. The installation of a cleanout located outside of the house will make future maintenance easier. You also won't have a mess in the house from the rodding work.