A cross bore occurs when one utility gets inadvertently installed through or damages another pre-existing utility. M.U.D. is concerned with situations where a natural gas pipe has been installed through a sewer lateral. A sewer lateral is the privately owned sewer pipe that connects a home or business to the city’s mainline sanitary sewer. The city’s mainline sanitary sewer is the large sewer pipe generally installed underneath the street.
Cross bores typically occur when a utility is installed using a trenchless installation method. Trenchless utility installations lead to cross bores because the construction personnel installing a new utility cannot see what is underground and therefore cannot avoid it.
M.U.D. prefers to install gas pipe using a trenchless installation method -- called directional boring -- because it limits the invasiveness of construction, especially in developed areas of the city. Directional boring involves digging a hole at the start of the pipe and one at the end. A directional boring machine then drills an underground hole between the two holes and pulls the entire pipe segment underground. In the past M.U.D. installed its gas pipe by digging a trench along the entire length of the pipe.
Directional boring is also safer for the residents in an area compared to having an open trench the entire length of the pipe. Directional boring is also quicker and more cost effective for our customer owners.
M.U.D. currently has contracts with Roto-Rooter and Backlund Plumbing to perform sewer lateral inspections for certain areas. These free safety inspections are to check for damage that may have occurred to the sewer pipe connecting your home to the mainline sanitary sewer, which is typically located under the street. Damage to this sewer pipe may have occurred during a previous underground natural gas pipe installation in the area. M.U.D. is proactively inspecting areas where this problem could have occurred.
A damaged sewer pipe could pose a safety risk to your home. If a plumber uses mechanical cleaning equipment in the damaged sewer pipe, the equipment could sever the nearby natural gas pipe causing natural gas to leak into your home. Because this is a safety issue that could affect multiple homes, on April 6, 2011 our Board of Directors approved an amendment to our Gas Rules and Regulations that allows M.U.D. to shut off a customer’s gas and/or water service if we are unable to inspect that property’s sewer pipe.
These inspections take between 30 and 60 minutes. During the inspection, the contractor will insert a small camera into your sewer lateral and attempt to inspect the pipe between your house and the mainline sanitary sewer.