Palo Alto launches gas-safety initiative

Inspections for residential and commercial gas line and sewer crossbores to begin in summer

The City of Palo Alto Utilities Department has launched a safety initiative to check local sewer systems for crossbores, which occur when a sewer line intersects a gas line, city officials said at a press conference Tuesday (April 26). While typically not a concern if left undisturbed, crossbores can become a major safety hazard when homeowners attempt to repair a sewer that is backing up.

"Certain types of machinery used by homeowners and plumbers to repair clogged sewers, such as snake machines and cutters, could cut the gas line intersecting the lateral, causing a gas leak," said Tomm Marshall, assistant director of Utilities.

"This is why it is important for residents who believe that they have a sewer blockage to contact the CPAU (City of Palo Alto Utilities) on a phone line that we have set up," he said.

The city will have engineers and contractors available at all times to be on site for crossbore inspection within two hours.

The department will run specialized miniature video cameras from the city's sewer mains through customers' individual sewer lines to search for crossbores.

The primary focuses for inspections are gas service that were installed or repaired between 1971 and 2001. It was during this period that the utilities department began to install gas service lines through horizontal or directional drilling, a technique that involved the digging of small underground tunnels through which new gas lines were pulled. While this process avoided the disruption caused by the digging of larger trenches, it is possible that on rare occasions the new gas pipes might have unintentionally bored through sewer lines that were placed differently than originally planned.

A total of $3.8 million has been budgeted to cover the costs of the inspections, which will run through 2013. Though officials noted that they do not expect for a vast amount of crossbores to be identified, if one is located, the city will remove and reroute the gas line and repair the sewer line, at no cost to customers.

The department has already begun inspections at high-occupancy buildings such as schools, hospitals and places of worship.

"So far, we have inspected 26 schools and found no evidence of crossbores," Marshall said. This phase of the project is expected to be completed by the end of summer.

The second phase will target commercial and residential locations, beginning in the middle of summer and ending by January 2013. A full schedule will be made available on the department's website.

"Crossbores are a safety risk across the country, and Palo Alto is one of the first utilities departments nationwide to have started a program specific to the problem," said Greg Scoby, engineering manager for Water, Gas and Wastewater.

Several measures have already been taken by the department to tackle the problem, he added. These have included the installation of new gas lines (beginning in 1999) that, if broken, immediately shut off the excess flow valve to reduce gas flows.

Residents can report a sewer blockage problem or suspected gas leak by calling 650-496-6995.

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Like this comment
Posted by Gunn Mom
a resident of Gunn High School
on Apr 26, 2011 at 8:45 pm

Glad to see Palo Alto taking the initiative on gas safety.

What do we hear from PG&E?

1 person likes this
Posted by BP Observer
a resident of Barron Park
on Apr 27, 2011 at 7:42 am

Are you kidding? PA Utilities is finally coming clean about all the gas lines they installed negligently, and they are now trying to portray themselves as saints by fixing the problem they created? How do you bore lines underground without knowing what you're boring through? Besides sewer, how many storm drain pipes did they bore through?
Again, the ratepayers will pay (nearly $4 million) to fix their screwup.

Like this comment
Posted by nat
a resident of Midtown
on Apr 27, 2011 at 1:07 pm

It isn't clear in the article if the sewer lines are the ones owned by the City, which are in the streets in residential areas, or if they include lines on private properties. I ask because the city does not unblock sewer lines on private property and people generally call plumbers to take care of them and do not check with the city about gas lines.So the question is: should the city be called first before calling a plumber for blockage on one's property. Perhaps the gas lines are all on the street and not in people's yards? I don't know. So these are questions to clear up with the city and with a follow-up article.

Like this comment
Posted by Joe
a resident of Barron Park
on Apr 27, 2011 at 1:54 pm

Yes, if you have a blockage in your sewer, you should call the City FIRST. The Utilities Department has a nice web page and video (Web Link) you may find helpful.

Your house sewer connects through a "lateral" to the City's sanitary sewer line (generally) located in the street. The lateral is the property owner's responsibility. As such, the lateral may or may not be located where the city thinks it is. Now, the City is concerned because the gas line running from the City's main to your house may have been installed directly through your sewer lateral. This might happen if the gas line was replaced by trenchless horizontal boring after your sewer line was installed. Apparently, the City found crossbores within their own storm drain system.

When fixing a sewer blockage, plumbers generally use either a "rod" or "cutter". A rod will generally push whatever's blocking the line all the way to the City's main in the street. Since the main has a larger diameter than your lateral, this is pretty simple. However, given the number of trees in Palo Alto and our climate, obstructions are made much worse because of tree roots entering the lateral looking for water. In that case, a plumber uses a cutter that's the diameter of your lateral to clear it. You can imagine that using a metal cutter on an active gas line is not a good thing to do.

So, be safe and call the City first if you have a problem. We had occasion to call them once late in the evening. They were quick to respond, professional, and very helpful.

1 person likes this
Posted by Bob Wenzlau
a resident of Crescent Park
on Apr 28, 2011 at 8:05 am

Bob Wenzlau is a registered user.

The City could possibly be more judicious in its choice to dedicated 3.4 million dollars to resolving this situation. The articles do not present how much of the $3.4 goes to repairing detected cross overs versus the detection of those same crossovers.

One observation is that the current (or interim) risk is greatest now, than it will be at the end of the expenditure, yet the use of the monies emphasizes final outcome rather than interim risk management procedures.

My initial focus would be on the interim, and consider including the following measures: 1) an ordinance requiring all sewer repair firms to register with the City and receive training, 2) the obligation of sewer repair companies to give notice to Palo Alto Fire or Utilities upon working on a sewer repair so that gas detection can occur at that point or juncture, 3) and the use of insurance policies to mitigate any damage in the interim rather than self-insure these risks, and 4) continued homeowner education including labeling of streetside cleanouts.

With a strong and deft interim risk management, the expenditure of $3.4 million comes into question. My hunch is that 80% of the expenditure is for detection and 20% for repair. I would challenge that the use of the 80% for detection is optimal, and that the interim programs could be adequate.

Some may push back and go ... "but if it were your house that blew up, would you not spend these monies" My response is that the current proposal appears to under emphasize the interim measures where the chance of damage is greatest, and provides unwarranted comfort in the effectiveness of the final measures.

I hope our Council engages staff with stronger discussion on this topic.

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Posted by anciana
a resident of Old Palo Alto
on Apr 28, 2011 at 10:40 am

I've had plumbers use cutters for my drains for the 50 years that I've lived in my house. My drains have been rotorooted a minimum of 30 times, probably many more times. Am I to wonder at this late date whether my lateral has a gasline problem? Wouldn't I know that by now? Good grief.

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Posted by nat
a resident of Midtown
on Apr 28, 2011 at 12:37 pm

I have the same feeling as "anciana" above. I can't remember the number of times during the 40 years I've lived in this house that I've had my drains unblocked without a problem. Is there any reason to worry now about a gas line? I would feel kind of silly calling out a worker from the city if there is no reason to.

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Posted by JQPublic
a resident of Crescent Park
on Apr 28, 2011 at 8:01 pm

I smell negligence.

1 person likes this
Posted by Sonny
a resident of College Terrace
on Apr 29, 2011 at 12:39 am

The question we should be asking the utility department is: how many of these cross directional bores were reported in the last few years? How many were deemed serious? And what is the underlying motivation to start investigating gas line installations that may be decades old. There is more to this story that what the city is offering.

Like this comment
Posted by Deep Throat
a resident of another community
on Apr 30, 2011 at 1:51 pm

The City doesn't want to spend enough money to keep the current minimum fire department staffing that serves as a de facto insurance policy in case there is fire, but the City is eager to spend money for this cross-bore utility line inspection for events (explosion and fire from gas lines due to work on sewer lines) that have a history of zero events a year. If nobody on the City staff is benefiting financially from this utility contract, the Cit employees are not as smart as I thought they were.

1 person likes this
Posted by Unhappy Neighbor
a resident of Charleston Gardens
on Apr 30, 2011 at 1:56 pm

Over 30 years ago the City promised to underground all the utility lines throughout Palo Alto. Nearly all north Palo Alto has been under grounded but only about one-third of south Palo Alto.

Now the City is taking $3.8 Million for their gas line project. Why aren't they using these funds to complete the under grounding of the utility lines in South Palo Alto? How long do we have to wait for our City to fulfill it's promise to complete the under grounding project?

Meanwhile, I have the ugliest utility pole with a huge transformer in my backyard. When I moved in 25 years ago I was told the City would be under grounding over the next two years and that pole would be gone. Here I am 23 years later and the pole is still there!!!

The City has its priorities wrong.

Like this comment
Posted by Hal
a resident of Leland Manor/Garland Drive
on Jun 13, 2012 at 2:32 pm

Well the "inspectors" came for a second time (3 months later) to inspect my lines because the 1st camera could not reach due to a tight turn. At any rate, I have 3 lines coming out of my home and it's odd that they would need to check 2 that are no way near the only gas line that services my home. Seems like a waste of money. Why not use a metal detector to map each gas line and then check to see if any sewer lines might cross based on the cleanouts? If so, then run a camera. Also, if a sewer line was replaced after the gas lines were bored, why would one need to inspect? I think they are mapping our lines so someday they can "tax" based on how many lines you have. Do you really think they are only looking for cross bores?
Remember they already charge for a bigger water or gas line. I could use less gas than my neighbor but if I have a bigger line, I pay more. Maybe they are looking for a future reason to charge more?

Like this comment
Posted by Crossbore
a resident of Downtown North
on Aug 29, 2015 at 9:48 pm

Was this program ever completed? I don't remember seeing completion or any updates? Wondering if this data can be used to save our trees from PG&E?

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Posted by Engineer
a resident of Downtown North
on Aug 29, 2015 at 10:34 pm

Why wait to the last minute and wind up with a haphazard map?

Why not just do a systematic camera survey of all laterals in areas where PAU records indicate trenchless gas pipe installation techniques were employed? Costs money, sure, but post-explosion, post-fire lawsuits cost lots, lots more. Ask PG&E.

In fact, it would seem criminally negligent if the PAU did not carry out the full survey immediately, given what it knows.

Meantime, I urge everyone to have a plumber do a camera inspection of their drain line before attempting any clog clearing. Pressurized gas from a penetrated gas pipe would enter your house through every drain. You could not stop it. It would ignite from any flame, pilot light, or spark. The explosion would be sudden, housewide, and devastating.

Like this comment
Posted by Neighbor
a resident of Old Palo Alto
on Aug 30, 2015 at 8:18 am

The city a few months back, will be changing ownership of the lateral sewer line, from the city to the residents. That is the clean-out near the sidewalk to the street.

Sorry, but further commenting on this topic has been closed.

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