Clogged sewer line? Always call us first at (650) 329-2579 to have the line cleared of a potential cross bore.
The City of Palo Alto leads with its proactive safety program to investigate unintended crossings between natural gas service pipelines and sanitary sewer laterals, known as cross bores.
In July 2011, the City began the first phase of the program and contracted with a sanitary sewer inspection company to look for potential natural gas cross bore. This project was completed in 2013. Approximately 7,000 sanitary sewer laterals were successfully verified and cleared from potential cross bore and CPAU Gas Operations subsequently repaired the identified 26 natural gas cross bore.
In August 2019, the City started the second phase of the safety program. 1,200 sanitary sewer laterals were scheduled for inspection. Due to the impact of COVID-19 pandemic on the construction industry, the contract was terminated. Approximately 400 sanitary sewer laterals were inspected, and no cross bores were found during the second phase of inspection. Prior to the shutdown, Churches and schools were inspected first, followed by various downtown neighborhoods. These sanitary sewer laterals were identified by the City as the highest priority.
Check out this short video created by the Mayor's Youth Video Corp in 2011 to get some background on the cross-bore issue and an update on how the City's inspection program is addressing it.
The City of Palo Alto will begin the third phase of the natural gas safety program in March 2020 to investigate unintended crossings between natural gas service pipelines and sanitary sewer laterals. The City is contracting with Cratus Inc to perform the third phase of the natural gas safety cross bore inspection program. The City reviewed and re-prioritized the remaining sanitary sewer laterals carried over from Phase I and Phase II projects. This phase will cover the inspection of approximately 1,400 sanitary sewer laterals which were determined to be the highest priority from the remaining sanitary sewer laterals.
Initial coordination with the City to schedule the sanitary sewer lateral inspection is not required. Cratus Inc. trucks will inspect all identified sanitary sewer laterals in the third phase of the safety program. If contract workers have issues accessing the properties sanitary sewer lateral, notification will be provided by a letter or door hanger requesting the property occupant call and schedule an appointment for inspection. In addition, the City contractor will comply with guidance issued by the County of Santa Clara Public Health Department. The City would also like to avoid face-to-face interaction between the residents and the City’s contractor and City staff, so information may be communicated by phone or email provided on the utility account.
For Your Safety, If You Experience a Sewer Lateral Back Up:
- Call 811 if you are planning on digging in your yard to check where your utility lines are.
- Do not use a sanitary sewer clearing machine to clear the sanitary sewer lateral until the obstruction has been assessed.
- If you smell a strong odor of natural gas or notice bubbles rising in the toilet bowl, immediately leave the premises while leaving exits open. From a safe distance, call 911 and City of Palo Alto Utilities at (650) 329 – 2579.
- Additional cross bore information is available in our brochure(PDF, 173KB).
Frequently Asked Questions
- What is a cross bore? Cross bore is the unintended conflict between one utility line through a portion of another utility line. This situation typically happens during construction using “horizontal directional drilling” or underground pneumatic boring. Our current safety program is focused on identifying natural gas cross bores where natural gas service pipelines pass through sanitary sewer pipelines.
- What is Horizontal Directional Drilling (HDD)? HDD is a method of trenchless construction where pipelines are installed underground. In the 1970s, the City began installing natural gas pipelines on customers’ private property through horizontal directional drilling. This eliminated the need to excavate across properties for the connection between the gas meter at the house and the gas distribution main in the street.
- How can a natural gas pipeline run through a sanitary sewer lateral without the utility’s knowledge? Since the tunnel drilling equipment is designed to cut right through rock and other hard surfaces without stopping, it can easily pass through a sewer pipe without giving the operator any indication that this has happened.
What to expect when we're inspecting:
- What is the City’s current inspection program? Since 2001, all Capital Improvement Gas Main Replacement Projects have included a requirement to video inspect sanitary sewer laterals and assess them from potential natural gas cross bore. In 2011, City crews started to conduct video inspections on the projects they have completed. From 2014 to present, City has its contractors perform video inspection after the installation of a new gas service pipeline on private property.
- What is the City’s schedule of cross bore inspections? Cross Bore Verification Program Phase III will begin in March 2020. Currently there are approximately 2,700 sewer laterals remaining to be video inspected. The City identified approximately 1,400 sanitary sewer laterals to be included in the third phase of the project. At this moment, the remaining 1,300 sanitary sewer laterals will be scheduled in the phase four of the project.
- Will I be notified when my property is inspected? The City will mail notification letters to each property owners at least thirty (30) days prior to the beginning of the project. The City contractor, Cratus Inc, will distribute notification to each property owner at least fifteen (15) days prior to the commencement of inspection activity. If re-inspection is required or if on-site access around your home is necessary to locate the private sewer cleanout(s) to complete the inspection, the City contractor will notify the property owner 24 hours prior to the inspection. In addition, the City would like to avoid face-to-face interactions between residents and the City’s contractor and staff, so information may be communicated by phone or email provided on the utility account. If the inspection does not occur after 20 days from the original notification, the City contractor will send another set of notification to the property owner.
- Do the City contractors carry ID? The City contractor will wear an identification card at all times during the inspection activity. Residents or property owners can verify the Contract workers by calling the City of Palo Alto Utilities Engineering at (650) 566-4501.
- What happens if my sewer line can't be easily inspected? The City’s contractor will place door hangers at each residence that require further investigation. These door hangers request that the affected property owner schedule an appointment for an on-site inspection.
- Will the City pay for a private sewer inspection before the City inspects my private sewer line? The City will not cover the inspection done by your own sewer cleaning professional. Property owners are responsible for all expenses incurred by sanitary sewer lateral inspection performed your own plumber (i.e., Non-City hired contractor).
- Will the City inspect for cross bores other than sanitary sewer lines and natural gas service pipelines? The 3nd phase of Cross Bore safety program will only focus on identifying cross bores resulting from the intersection between natural gas service pipelines and sanitary sewer laterals.
More crossbore background:
- How many crossbones are in Palo Alto? During the 1st phase of Cross Bore Verification Program from 2011 to 2013, 56 cross bores were identified. Of the 56 cross bores identified, 26 were natural gas.
- Are there cross bores involving other utilities? (electric, cable and water)? There are 30 cross bores identified that are not natural gas cross bore in the 1st phase of the program.
- How many cross bores have resulted in fires or explosion in Palo Alto? None.
- Is the City now inspecting every sewer line in Palo Alto? In 2014, the city started conducting post video inspection after new installation of natural gas service pipelines.
- How will the City be changing installation and inspection practices in the future so that cross bores are eliminated? At this time, there are approximately 2,700 sewer laterals remaining to be video inspected. The City identified approximately 1,400 sanitary sewer laterals to be included in the third phase of the project. The remaining 1,300 sanitary sewer laterals will be scheduled to complete on the phase four of the project. From 2014 to present, the newly installed natural gas service pipelines require post-construction video inspection of sanitary sewer laterals.
- Doesn’t the building inspection department have to approve the installation or replacement of natural gas lines to ensure that they are safe? No. Utility owned infrastructure is regulated by the U.S. Department of Transportation and natural gas infrastructure matters are not subject to local building codes.
- Does the City have records of the private sewer line? No. The City does not have records of the private sewer line because local building codes do not require the submission of record drawings which would reflect what was installed by the plumber. Also, the property owner may make additional repairs or changes to the sewer line at a later time after a permit has been issued. For these reasons, the exact location of a private sanitary sewer lateral is still not known.
- Will I see higher gas or wastewater rates as a result of this program? No, this program is funded through the Utilities Department's existing preventative maintenance program.
- What will it cost to fix this problem? Council approved $1,682,000 for the 3rd Phase of Cross Bore Safety Program over a two-year period.
- How do I make sure to get the latest information? Sign up on our email list to get updates on programs, rebates and workshops, or go to our Twitter Feed or Facebook page to get the latest.