Sewer system failures aren’t just possible, they’re inevitable. Any number of threats can cause failures that lead to backups and cost taxpayers money.

Major storms, which are on the rise, put pressure on aging infrastructure. When systems become overloaded and pipes and pump stations are pushed to the brink, catastrophic sewer failures can result, causing environmental and public health disasters.

Storms expose infrastructure vulnerabilities that municipal wastewater system managers typically have every intention to address before a larger storm hits. However, too often, planning for future failures slips down the priority list after repair and cleanup is completed due to busy schedules and tight budgets.

Even in the absence of a major storm, aging wastewater infrastructure can break down with little warning. Preparing for sewer system failure can significantly reduce the severity of a failure, its environmental impact and the cost to taxpayers.

Understand the system’s vulnerabilities

To prepare for failures and overflows and reduce their impact, municipal wastewater system managers should first understand how and where the system is most likely to fail. When conducting a risk assessment, factors to consider include:

The age and condition of the pumps and pipes. Older pumps are more likely to fail, and when they do, it may be difficult to find replacement parts. Older pipes are more likely to crack or corrode.

System design. Was the system designed to handle heavy rainfall and flooding caused by intense storms? Is the changing weather pattern in the area bringing more of these storms? What low-lying areas are most vulnerable?

Typical flows. If the system was designed for more flow than it receives, stagnant sewage or slow flow can cause hydrogen sulfide to build up at the crown of the pipe. This build up can lead to corroding of the pipe and can increase the risk of a break.

Flushed materials. One cause of pump station failure unrelated to storms is solid materials that clog systems. These materials include “flushable” wipes, which don’t easily degrade in a sewer system. Solid materials can clog both pipes and pumps, causing stoppages that lead to the backup of raw sewage into homes.

Current maintenance. A well-maintained system is better able to withstand extra flow. Regular cleaning reduces the accumulation of grease, fats and other substances that narrow pipes.

Create a contingency plan

Municipal wastewater system managers need to act immediately when a system failure occurs. A clear, well-thought-out contingency plan enables a faster, more effective response.

Contingency plans should take into account practical considerations of bypass and repair. This includes assessing the real estate surrounding vulnerable parts of the system. Is there enough space to place pumps? Will hoses have to be run across a major roadway? Similarly, will it be necessary to bypass the force main, or does it have a flanged connection? Where will the sewage be discharged?

Create a bill of materials

Once you’ve identified vulnerable system components, you should develop a bill of materials required for emergency repairs. Include all necessary parts and tools, such as:

• Pumps (sizes and types)
• Pipes (sizes)
• Hoses (material, width, and length)
• Valves and fittings (quantity and type)
• Mobile generators

Create a CAD drawing

A CAD drawing of the sewer system makes it easier for operators or third-party contractors to understand where and how the equipment and parts are meant to be used. Faster implementation of repairs reduces the impact of failures and the cost of cleanup.

Partner with a trusted equipment vendor

Partnering with a company that has the necessary rental equipment as well as experience in contingency planning for wastewater systems can help municipalities prepare effectively for sewer system emergencies.

With supply chain shortages, choosing a vendor with a large inventory of available equipment is vital. Some rental companies may not be able to quickly provide all the items on a bill of materials when the time comes. Equally important is 24/7 customer service since failures don’t always happen during normal business hours. Managers should ask the vendors they’re considering about their availability and response time in emergency situations.

When a sewer failure occurs, the clock starts ticking. Every minute of overflow increases the risk to public health, the cost of cleanup and the number of angry constituents. A rapid response enabled by advance planning and immediate equipment availability can save money, reputations and jobs. More important, it can reduce the risk of illness and environmental contamination caused by untreated sewage spills.

Contact the United Rentals Fluid Solutions team to get started on an effective response plan for sewer system emergencies.