Common Problems in sewer lines-Pipe offset problems

Underground pipes are installed in sections or segments ranging from 2′ to 20′ or more. When connected sections do not line up perfectly with one another, they are referred to as being “off-set.”

Sewer lines built from the 1800’s up to the mid 1980’s were constructed using a large number of short sections, typically 2′ to 4′ in length, of VCT (vitreous clay tile) pipe. These sewer lines are particularly subject to off-sets due to their large number of joints. During construction, the joints were sealed with products such as concrete, coal tar, oakum, rubber gaskets, and on occasion, nothing at all. Over time, these sealants erode away, allowing the pipe to then settle down into the “hub” of a connected pipe creating a slight offset. In most clay pipe, off-sets will not exceed 1/4″ unless the pipe is broken at the hub. However, this only applied to pipes running in a straight line.

Most sewer camera systems will have a very difficult (if not impossible) time passing over a 1/4″ off-set. If a sewer line is being video inspected and the technician passes over what he is calling a “severe off-set” and suggests excavation work is needed…beware. Compare his evaluation to those controlled models pictured here.

Common Problems in sewer lines-Pipe offset problems

Common Problems in sewer lines-Pipe offset problems

Hydro Physics recently did a re-inspection after a well-known drain cleaning company “documented” four 1″ off-sets with an accompanying $14,800 repair estimate. We found these off-sets to actually be 1/8″, well within the acceptable range, and that no repair work was needed.

Hydro Physics is the technology leader with more than 20 years in the pipe inspection industry. We are the only company licensed to apply Vaporooter in Colorado. We are committed to providing high-quality, camera pipeline inspection videos/reports. We offer highly trained inspection experts for a safe, cost effective, environmentally-responsible service. You benefit from this unbiased, accurate report, perhaps saving you thousands of dollars. We saved our clients $253,000 in just the first half of 2015 in unneeded sewer line repairs. We create value to our customers by supplying high-quality color videos and written reports for better pipe analysis. We offer
• Pipe inspection,
• utility locating,
• odor detection,
• leak detection,
• pressure testing and
• root removal using Vaporooter.

Our company goal remains the same, to expose fraud in the pipe inspection business estimated to be $20,000,000 (million) a year in the Denver area. Visit our website at

Specialties: Sewer and pipe video inspections of all piping 2″ to 60″ in diameter that are guaranteed accurate and unbiased. Serving Metro Denver and Fort Collins, Colorado. Ideal for home buyers and home owners who want to verify proposed repairs.