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.

Failing sanitary sewer systems are confronting American cities of all sizes. Many systems are operating beyond capacity and old underground infrastructure is crumbling with infiltration causing overflows following heavy rains and leaking sewage contaminating groundwater. Many systems are operating under U.S. Environmental Protection Agency consent decrees in which customers ultimately pay for correcting serious deficiencies.

Laterals that connect sewer mains with homes and buildings of customers are an essential part of every sewer system. But as major projects replace and rehabilitate thousands of miles of sewer mains, the condition of laterals is largely ignored, even though failing laterals may be responsible for a significant portion of a system’s inflow and infiltration (I&I). Every sewer system is different, but estimates of I&I attributed to laterals range from 25 to more than 50 percent.

Why aren’t sewer laterals receiving the same attention as main lines?

This report is the first of three that will ponder that question and options to address failing laterals. This report considers the condition of sewer laterals in the U.S. and factors that contributed to today’s problems.

Integral part
Laterals clearly are an integral part of a sanitary sewer system, yet most municipalities and water and sewer districts consider laterals the property and responsibility of the owner of the property through which they pass.

“Laterals are on private property and, therefore, generally considered the responsibility of the property owner,” says Gerry Muenchmeyer, P.E., Muenchmeyer Associates LLC, and technical director of NASSCO (National Association of Sewer Service Companies). “In many municipalities sewer laterals -- other than vertical riser connections -- are not accepted as the responsibility of the city. In other areas, the municipality assumes responsibility for the lateral sewer only from the mainline to the property line.”

Unless the municipality has initiated a program to renew or replace sewer laterals, it is widely considered the property owner’s responsibility to maintain, repair or replace lateral pipe in the event it no longer functions, an obligation most property owners are unaware of and unprepared to do.

Most people, Muenchmeyer observes, take sewers for granted, including main lines and laterals.