Dealing With Laterals: Abundant Challenges

Part 1 Of An Exclusive 3-Part Series
By Jeff Griffin, Senior Editor | September 2010 Vol. 65 No. 9
A Hoffman Southwest crew installs a lateral.

“Many homeowners are probably not even aware of what happens when a facility is flushed in their home,” he continues. “Certainly maintaining the condition of their sewer laterals is not a priority. Money is more readily spent for landscaping and surface improvements that can be visually appreciated, rather than a pipe which is only important when a flush is no longer available.”

As a result of system owners avoidance of responsibility for laterals and property owners unawareness that in case of a failure they may be responsible, a large percentage of laterals in the U.S. are old and have received no maintenance since they were put in the ground.

In addition, the piping used for laterals and the ways in which they were constructed has contributed to their generally poor condition.

“Pipe material for laterals generally has been lower in cost and quality and installed without any municipal inspection,” says Muenchmeyer. “Unlike mainline sewers that were typically installed in a straight alignment between manholes, lateral sewers were installed with a multiple number of bends and fittings. And though generally infrequent, mainline sewers have received some measure of maintenance by the municipality while lateral sewers typically deteriorate to a point where major renewal or replacement is required.”

I&I
George Kurz, P.E., DEE, senior technical leader, Barge Waggoner Sumner & Cannon Inc., has conducted extensive research and documentation of lateral I&I issues.

“Leaking sewer service laterals represent a significant component of I&I in sewer systems,” says Kurz. “Also, I think that it is possible to estimate the percentage of I&I that can be attributed to failing laterals, and better yet, it has been demonstrated that the percentage can be measured under certain circumstances.”

Kurz cautions that methodology of previous studies has varied widely influencing the resulting estimate of I&I levels.

“The real message,” he says, “is that lateral and manhole rehabilitation must always be a part of the overall rehabilitation project. I call this the ‘system approach’.”

Hoffman Southwest Corp. operates Roto Rooter franchises in California, Oregon, Arizona and Utah and its personnel service hundreds of sewer laterals every day.