Should I be concerned?

Actually, any defect in the sanitary sewer system is a cause for concern, not only due to the possibility of an influx of stormwater into the system, but also the possibility of allowing the escape of watewater and gas. A sanitary sewer system typically contains chemicals and gases that can pose a significant danger. For example, personnel working in manholes wear protective suits, and gas detectors continually monitor the manhole environment for the presence of hydrogen sulfide as well as other toxic gases. Should there be a break or defect in the sewer line in or under your residence, wastewater and gas could enter your dwelling. That's why it's so important that the defects be identified and repaired! And frequently, the only way such flaws can be correctly identified is for trained personnel to enter the residence and survey the structure.