News Release News Release The City of Palo Alto
Communications Department
250 Hamilton Ave
Palo Alto, CA 94301


Subject :

City of Palo Alto Launches New Gas Safety Initiative
Contact : Mary Coady, Utilities Commnications Manager, Utilities    650-329-2479
Palo Alto, CA --  The City of Palo Alto Utilities Department (CPAU) has announced a new gas safety initiative, launched as an important component in its ongoing gas safety activity.

Under this initiative, the Utilities Department will visually inspect sewer laterals throughout the city at homes and businesses to identify and repair any situation where a gas line passes through or intersects a sewer line, a condition known as a crossbore.  Palo Alto is a leader in implementing this program, which addresses an issue that occurs in communities throughout the nation.

Crossbores typically are not a risk if left undisturbed.  However, a safety risk exists in cases when a homeowner or plumber attempts repair work to a sewer line using a mechanical cleaning device such as a cutter or snake machine.  The cleaning device may sever a gas line and cause a resulting gas leak, which could result in a dangerous situation.

As part of the City-wide, comprehensive inspection process, crews will use video technology to run cameras from sewer mains through customers' sewer lines.  The City will repair any crossbore occurrences by rerouting gas lines, as well as replacing or repairing affected customers’ sewer lines.  In the course of this examination, the City may find non-crossbore related problems with a sewer line.  The City will inform customers if their sewer lines appear to need repair, and, upon request, will provide customers with a digital copy of the video for their personal use.

In the event of a sewer emergency, the City will have crews available on a round-the-clock basis for quick response.  "The key message for our customers is this: if you believe you have a sewer blockage problem, call the City of Palo Alto Utilities Department first at (650) 496-6995.  We will have trained staff available to respond 24x7. They will assess the area for crossbore and determine additional precautions or next steps," said Javad Ghaffari, Manager of Water, Gas and Wastewater Operations.

“CPAU conducts on-going maintenance and upgrade programs to assure the integrity of its gas system.  In reviewing our operations and best practices and in response to heightened concerns around gas system safety, we recently conducted an intensive review of current system conditions to determine the existence of potential hazards to our customers.  Although the issue of crossbore safety is a national one, CPAU is among the first utilities in the country to undertake a very aggressive crossbore safety program,” said Greg Scoby, Water, Gas and Wastewater Engineering Manager.

The Utilities Department has begun inspecting schools, places of worship and other large gathering sites.  Following that, it will begin inspection of other sites throughout the city. This program is expected to be completed by January 2013. 

Industry data shows that crossbores exist in a rare number of cases. The occurrence of crossbore began with the use of trenchless underground utility construction methods.  These methods, including horizontal directional drilling and pneumatic boring, eliminated the disarray caused by the older method of digging trenches across property and through yards.  The trenchless techniques involve creation of a small underground tunnel through the soil, through which a new utility line is pulled. 

In using these trenchless methods, generally in the period between 1970 and 2000, the industry undertook all standard precautions to place new pipes in areas removed from other underground utilities, including water and sewer lines.  However, not all sewer lines follow the expected alignments, as a result of remodeling, re-landscaping or other activity.  In those cases, the boring equipment operator could inadvertently bore through a sewer lateral while installing another utility line at intersection with the sewer pipe.  Because the boring equipment is designed to cut through hard materials, these crossbores could be undetected during construction.

Improvements in technology and construction practices have reduced the possibility of crossbore during the past decade.  In 1999, the CPAU began installing safety devices known as excess flow valves, which restrict gas flow in the event of a service line severance. CPAU has employed advances in video technology to efficiently inspect sewer lines both before and after installing another utility line. As a result, in 2001, CPAU began a practice of video inspecting sewer lines on properties where gas lines were replaced.

“I support taking an aggressive stance in addressing the issue of crossbore,” said City Manager James Keene.  “We believe that adoption of a program that resolves any crossbore situations is a necessary investment in the safety and well-being of our community.”

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out the City of Palo Alto Utilities

CPAU is the only publicly-owned utility in California that provides a full complement of utilities services, including electric, fiber optic, natural gas, water and wastewater.  The City of Palo Alto Utilities has been delivering quality services to the citizens and businesses of Palo Alto since 1896.  For more information, visit us on the web at