Case Study: Severe Sewer-Main Blockage

Manhole Cover

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Sewage backups – they can be one of the most hazardous things that can happen in a place of business or home. Not only can they cause significant health issues for anyone exposed to the area, but they may also cause thousands of dollars in damage to underground piping and any surrounding areas.

In May, 2014 Helfrich-Associates was called in to assess an insurance claim for sewer damage in The City of Burbank, California. The damage occurred when a sewer-main blockage caused sewage to spill onto a commercial property.

Our team was called in to address the following questions:

  1. Did a design or construction issue cause the event?
  2. Did a maintenance issue cause the event?
  3. Was the event sudden and accidental?

As part of our investigation, we conducted a video analysis of the clogged sewer line. One of the challenges we faced during the analysis was severe waste build-up in the pipe, which was so severe that the camera got stuck. The plumbing video technician could not snake the line due to the build-up. Access was achieved via a clean-out in an outdoor seating area. This section of sewer line was downstream and debris, sand, small rocks, and toilet paper were found.

Helfrich-Associates also conducted a review of the location’s maintenance records for the past four years.

After examining all of the data collected, we were able to surmise that grease build up was the determining factor for this blockage. A review of the grease interceptor logs provided the following information:

  1. The grease interceptor had overflowed multiple times due to sewage backing up in the grease interceptor.
  2. The City of Burbank regulations require that grease interceptors should be pumped and cleaned on a regular basis. This ensures that any combined fats, oils, grease and solids accumulation does not exceed 25 percent of the total liquid depth of the grease interceptor.

Upon review of maintenance documentation, on-site inspection, and plumbing charges, we concluded that sewer backups had been occurring over the last four years. The discharge line from the grease interceptor had deteriorated, allowing sewage to back up causing the sewer main blockages.

The May 2014 event was one of many blockages that had occurred at this site. A Helfrich-Associates engineering report was submitted to the insurance company to use in their evaluation of insurance policy coverage issues.

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If you need help with severe sewer line issues we may be able to help. Contact us for more information.

Have you ever experienced a sewer backup in your home or business? How was it resolved? Let us know in the comments, below.

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