The Rodent Dilemma

Throughout the United States, infrastructural decay of an unprecedented level has led to widespread damage contributing to the failure of sewer systems. Hidden below the ground, people rarely think about these systems because they are out of sight; however, they are one of the most important infrastructures that play a vital role in public health and safety. When sewer system decay is combined with rats’ swimming abilities, serious problems begin to start. Rats are capable of swimming as far as one half mile while going against substantial currents in sewer lines, and they are able to swim through water traps in plumbing. This means that rats are often literally under our feet, and their populations in the sewer system are rapidly increasing.A U.S. Senate Hearing discovered in 2011 that it would require approximately $330 billion to upgrade sewer systems throughout the nation. Along with this discovery, an American Society of Civil Engineers’ study revealed that an additional amount of $9.2 billion per year is necessary for repairing and maintaining water and sewer systems through to the year 2020. During this time, increased interruptions in the supply of water and frequent contaminations from sewer micros will become normal for our population. It is also projected that increased pest populations will begin to emerge directly from beneath our feet.While this may seem to be a daunting challenge, it offers a new opportunity for pest management professionals to raise public awareness regarding the importance of making sewer system inspections as essential and common as those regions such as building exteriors and interiors, roofs, traffic systems and landscaping. Raising sewer system awareness is best accomplished through the combination of proactive and failure-based camera inspections conducted by a licensed plumber.

  • A licensed plumbing contractor or licensed plumber should be subcontracted to provide periodic camera inspections of the sewer line and document all findings.
  • These inspections should be documented as a portion of the Master Cleaning Schedule or any related document.
  • Corrective strategies for failing sewer lines should be implemented.
  • Repairs and replacements of known sewer line failures should be facilitated.

Sewer systems provide rats with potential routes of entry into other structures. Rats have been observed wriggling up through sewer lines and out of toilets. To prevent this, the following strategies should be implemented:

  • Metal grates with an opening of less than ¼ inch across should be installed and secured over floor drains.
  • A licensed plumber should install sewer floor drain back-up preventers.
  • Decision-makers should work alongside local sanitation and health departments to implement management programs designed specifically to handle sewer system rats.
  • The use of rodenticide bait block applications in sewers should be done according to the label. This may involve running a wire through holes located in the bait blocks, and then attaching the wire to a stationary structure such as a sewer grate. Properly securing blocks will ensure that they are not removed by rats or water. Typically, 12 bait blocks are needed per manhole.
  • When using rodenticide, it is essential to protect human health and safety by fully understanding and following the label.

It is expected that the current trend of decaying sewer systems will continue to be a major challenge for municipalities in the upcoming years. As aging leads to decay, sewer systems will experience an increase in invasive pests. The significant need for prompt action will create revenue opportunities for pest specialists who understand how to manage rat populations that are spreading below the city surface.