When to Replace Stormwater Infrastructure

Stormwater infrastructure is an important part of a city’s infrastructure system. With around 3.5 million miles of sewers in the US, stormwater infrastructure upkeep can be hard for municipalities to manage. Over time, however, these systems can deteriorate and become less effective.

Knowing the warning signs of when to replace stormwater infrastructure is important for maintaining safe and efficient sewers. Here are some of the warning signs that indicate a need for stormwater infrastructure replacement:


Old rusted sewer by lawn curb.

The age of a sewer system is one of the most important factors to consider. Depending on upkeep and the materials used, stormwater infrastructure has an average lifespan of between 20 to 100 years. If the infrastructure is reaching the end of its lifespan, it may be time to consider replacement.

The age of stormwater infrastructure is an important factor to consider when evaluating its condition and performance. The lifespan of the infrastructure can vary widely depending on several factors. These include the materials used, the quality of construction, and the level of maintenance received over time.

For example, concrete pipes and culverts can become brittle over time, leading to cracking and failure. Steel pipes can rust and corrode, reducing their strength and integrity. Additionally, sediment and debris can accumulate inside pipes and culverts. This reduces their capacity and increases the risk of blockages and flooding.

Factors That Lower Lifespans of Wastewater Systems

Neglecting Maintenance and Inspections for Aging Wastewater Systems

Regular inspections and maintenance help to identify signs of aging and deterioration in stormwater infrastructure. This allows for stormwater repair and replacement to be made before more serious issues arise. However, as infrastructure reaches the end of its expected lifespan, it may be more cost-effective to replace. This is especially true if there is a need to frequently issue repairs and patchwork fixes.

Environmental Wear and Tear

It is also worth noting that the lifespan of sewers are impacted by factors beyond municipalities control. For example, extreme weather events or natural disasters can cause significant damage to infrastructure.

Similarly, changes in land use and development can lead to increased runoff and stormwater flows. This puts additional stress on aging infrastructure and reduces its effectiveness, which increases the need for stormwater repair and replacement.

Physical Condition

close-up of ruptured sewer rusty pipeline which cause sewage leakage stream and pollution. old infrastructure issues in the city construction site

The physical condition of stormwater infrastructure is an important factor to consider when assessing its performance and safety. As infrastructure ages and is exposed to the elements, it can experience wear and tear that can lead to structural damage and other issues.

One of the most common signs of physical damage to stormwater infrastructure is cracking. Concrete pipes and culverts, for example, can develop cracks as they age. These cracks allow water to seep through and cause erosion or instability. Similarly, steel pipes can also develop cracks due to fatigue, stress, or corrosion.

Other signs of physical damage in need of stormwater repair can include deformation or buckling. In some cases, these signs of damage can be visible on the surface. However, many times they may only be detectable through more in-depth inspection techniques, such as GIS Mapping.

For underground pipes, physical damage can be particularly problematic, as it can be difficult to detect and repair. Leaks or blockages in underground pipes can lead to a variety of issues. Examples include sinkholes, flooding, or damage to nearby structures. As such, regular inspection and maintenance of underground pipes is essential to ensure their continued performance and safety.

Here are some signs that your infrastructure is damaged that may be visible on the surface:

Here’s how you can tell if a stormwater pipe is potentially cracked or corroded without digging:

  • Visible cracks: One of the most obvious signs of a cracked pipe is a visible crack or fissure in the pipe material. These cracks can occur due to age, wear and tear, or physical damage.
  • Changes in water flow: If the flow of water through a pipe suddenly changes, it can be a sign that there is a crack or other damage that is causing water to leak out of the pipe.
  • Sinkholes or depressions: When a stormwater pipe is cracked or damaged, water can leak out and cause erosion of the surrounding soil. This can lead to sinkholes or depressions in the ground above the pipe.
  • Wet spots or standing water: If there are wet spots or standing water in an area where it is not supposed to be, it can be a sign of a cracked or damaged pipe that is allowing water to leak out.
  • Unusual odors: If there is a strong or unusual odor in an area where stormwater infrastructure is located, it can be a sign of a cracked or damaged pipe that is allowing sewage or other materials to leak out.
  • Discoloration: Discoloration or staining on the surface of a pipe can indicate that it is corroding or deteriorating and may be at risk of cracking or other damage.

Capacity Issues

Drain in need of sewer repair not draining properly with construction cones next to it.

The capacity of stormwater infrastructure is a critical factor in its ability to effectively manage stormwater runoff. Low capacity can lead to flooding, erosion, and other issues that can pose a risk to public safety and property.

Factors That Impact Stormwater and Sewer Capacity

Size of the Infrastructure is Not Optimal

One important consideration when evaluating capacity is the size of the infrastructure relative to the area it serves. If the infrastructure is too small, it won’t effectively manage the volume of water generated during heavy rainfall events. This leads to flooding and other issues. Conversely, if the infrastructure is too large, it may be underutilized, leading to inefficiencies and wasted resources.

Blockages Have Caused Damage Due to Inefficient Maintenance

Another important consideration when evaluating capacity is the condition of the infrastructure. Over time, stormwater infrastructure can become clogged with sediment, debris, or other materials. This reduces its effective capacity and increases the risk of blockages and flooding. Similarly, physical damage to infrastructure, such as cracking or corrosion, can also reduce its capacity and effectiveness.

Infrastructure Has Not Expanded With Population Increases

Stormwater repair and expansion should also increase along with population increases. This is to accommodate the increased volume of water generated by runoff. This can involve adding new infrastructure or upgrading existing infrastructure to increase its capacity and effectiveness.

Additionally, it may involve implementing new stormwater management techniques, such as green infrastructure.

Maintenance Needs Have Significantly Increased

Two construction workers uses shovels to dig up a sewer pipe for sewer maintenance and stormwater repair.

According to the Congressional Budget Office, in 2017:

  • 72% of wastewater spending in the United States was used for Operation and Maintenance.
  • 96% of this government spending was state and local governments.
  • Government spending reached $113 billion in 2017 for water supply and wastewater treatment.

As mentioned earlier, regular maintenance is crucial for ensuring the longevity and effectiveness of stormwater infrastructure. Neglecting maintenance can cause various problems, which can make replacement of the infrastructure necessary. Regular maintenance activities include inspections, cleaning, repairs, and replacements of worn or damaged parts.

Procedures Necessary for Proper Water Systems Maintenance

Regular Inspections to Check for Damage and Blockages

Inspections are crucial to identify any signs of wear and tear, cracks, or other types of damage. Inspections should be performed regularly to detect any potential issues and address them promptly. While you should inspect your water systems at least once a year, preventative measures will be the best option to keep both costs and potential issues low.

Regular Cleaning

Cleaning of stormwater infrastructure is another important maintenance activity that should be performed regularly. Sediment, debris, and other materials can accumulate inside pipes, which can reduce their capacity and effectiveness. Regular cleaning can lower the frequency of needed stormwater repair, which will lead to a longer lasting sewer system.

Repair and Replace Before Severe Damage Occurs

While regular maintenance is a key component of longevity, sewer repairs and replacements are inevitable. If a section of pipe has a severe crack, corrosion, or other damage, it may be necessary to replace that section of the pipe. Similarly, other parts of the infrastructure, such as catch basins, manholes, or headwalls, may also need to be replaced if they become damaged or worn out.


Outdated Technology, Materials or Design

Older rusty pipe needing sewer replacement draining into a creek.

Over time, technology and best practices for managing stormwater and stormwater repair can change. These changes can impact the design and effectiveness of stormwater infrastructure. As a result, infrastructure that was considered state-of-the-art a few decades ago may now be outdated and unable to meet current needs.


One common example of this is the use of traditional concrete pipes for stormwater conveyance. While concrete pipes can be effective in managing stormwater in some circumstances, they can be prone to cracking, corrosion, and other types of damage that can reduce their effectiveness.

Additionally, concrete pipes may not be able to handle the increased volume of water that is generated by more intense and frequent rainfall events. In these cases, an upgrade to more modern materials, such as HDPE (high-density polyethylene) pipes, may be necessary to ensure the infrastructure is able to manage stormwater effectively.


Similarly, the design and location of stormwater infrastructure may need to be updated to meet new best practices or regulations. For example, in some cases, green infrastructure techniques such as bioswales, rain gardens, or permeable pavements may be more effective at managing stormwater runoff than traditional infrastructure.

If an area has been developed since the stormwater infrastructure was initially installed, it may be necessary to adjust the design and location of the infrastructure to accommodate the changes in land use and runoff.


Another example of upgrades to stormwater infrastructure is the use of technology to improve the performance of the system. For instance, real-time sensors can be used to monitor water levels, flow rates, and other parameters to provide data for optimizing the system’s performance.

Advanced analytics, data visualization, and modeling can be used to process this data to provide insights for system managers, such as identifying areas where blockages or other problems are likely to occur. If the existing infrastructure is not capable of supporting these technologies, an upgrade may be necessary to take advantage of the benefits they provide.


Recent Flooding

Broken sewer drain on city street needing stormwater repair. Flooding water flows out of manhole.

Since 1996, 99% of counties in the United States have been impacted by a flooding event. Flooding is one of the most visible and immediate signs that stormwater infrastructure may need to be replaced. If the system is not functioning effectively, it may not be able to manage the volume of water that is generated during heavy rainstorms, leading to flooding that can cause significant damage to properties and pose a hazard to public health.

In many cases, flooding is the result of an overloaded stormwater system that cannot keep up with the volume of water that is flowing into it. This can occur if the infrastructure is too small or if it is not functioning properly due to damage or blockages. As a result, water can back up into streets, homes, and other structures, causing damage and posing a hazard to public health.

Flooding can be particularly dangerous if it is a recurring issue, as this can indicate that the stormwater infrastructure is consistently failing to manage the volume of water that is generated during storm events. This can lead to chronic property damage, as well as increased risks of water-borne diseases and other public health hazards.

To address the issue of flooding, cities and municipalities may need to consider replacing stormwater infrastructure that is consistently failing to manage stormwater effectively. This may involve increasing the size of the infrastructure, installing more effective drainage systems, or upgrading the technology used to manage the flow of water through the system.

In some cases, it may be necessary to completely replace the existing infrastructure, particularly if it is outdated or otherwise unable to meet current needs.


Cost of Stormwater Repair Outweighs Replacement Cost

Replacing an underground pipe using a crane and chain.

Cost is an important factor to consider when deciding whether to replace or issue stormwater repair. While replacing infrastructure can be expensive, replacing is often less expensive than the cost of repairing damage caused by outdated water infrastructure. This is often true for other problems that result from outdated or damaged infrastructure as well.

Reasons to Replace vs Repair Outdated or Damaged Stormwater Infrastructure

Damage is too Frequent or Severe to Patch, Making Failure More Likely

When infrastructure is outdated or damaged, it is more likely to fail and cause damage to properties and other structures. This can result in expensive repairs and clean-up costs. These costs can be significantly more expensive than simply replacing the infrastructure when you also factor in surrounding damage and legal fees.

Legal Liabilities for Damages Caused by Failed Water Infrastructure

In addition, damaged infrastructure increases the risk of legal liability for cities and municipalities. If infrastructure fails, the municipality responsible for maintaining the infrastructure may be held legally responsible for the damage. This can result in expensive legal fees and settlements, which can be avoided by proactively replacing outdated or damaged infrastructure.

Longterm Infrastructure Investments Lower Overall Costs and Risks

The cost of replacing stormwater infrastructure can be a significant investment. However, it is important to view this investment in the context of the long-term benefits that it can provide.

By investing in modern, effective infrastructure, cities and municipalities can better protect their communities from the risks of stormwater-related damage.  This also ensures that they are able to manage stormwater in a way that is sustainable and environmentally responsible.

Why You Need an Experienced Team for Stormwater Infrastructure Replacement

Additionally, it’s also important to work with an experienced team for stormwater infrastructure replacement. This will ensure you get the most effective and long-lasting sewer system along with lowering your costs in the long run due to fewer repairs and less immediate maintenance.

Another key benefit of working with an experienced team is that they have the knowledge and experience to manage any unexpected issues that may arise during the replacement process. Stormwater repair and replacement can be unpredictable if not done correctly.

It is not uncommon for unexpected issues to arise during the process. An experienced team like GBA will quickly and effectively prevent and address these issues, minimizing any delays or disruptions to the replacement process.

Ultimately, working with an experienced team for stormwater infrastructure replacement can help ensure that the replacement is done effectively and efficiently, with minimal disruption to the surrounding community. By partnering with a team that has the knowledge, skills, and equipment necessary for the job, municipalities can make the replacement process as seamless as possible.

In Conclusion

Stormwater infrastructure plays an important role in managing runoff from storms and reducing the risk of flooding. Regular stormwater repair, inspections, and maintenance help to prolong the lifespan of the infrastructure. However, eventually, replacement will become necessary.

By paying attention to the warning signs discussed above, engineers and city officials can ensure that stormwater infrastructure is replaced in a timely manner to maintain a safe and efficient infrastructure system.

If you are a municipality and are concerned you might need to replace part of your stormwater system, you can reach out to GBA on our Contact Page.
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