In many of our communities, stormwater and wastewater infrastructure is reaching the end of their useful lifespans. At the same time, since these systems were first constructed, demand has increased because of more people, more impervious surfaces, and more frequent storms. 

As communities across the country work to manage their water, applying principles established under the One Water concept ensures a greater degree of longevity and sustainability: some of us have too much water, some of us have too little, and all of us need fresh, clean water to survive and thrive. 

It’s surprising to consider that every component of society—from water, infrastructure, urbanization, climate, and population growth—impacts the performance of our built and natural ecosystems.

Here are 78 statistics and trends that put the state of our cities in context and give us the tools necessary to start solving problems—together.

  • Flooding, Precipitation & Climate Change
  • The Impact of Climate Change on Infrastructure
  • Managing the Difference Between Stormwater and Wastewater
  • The Current Landscape of Cities and Urban Ecosystems
  • Time for Investment in Climate Technology

Flooding, Precipitation & Climate Change

It’s the 2020s and climate change is no longer in question. Regardless of whether we agree on the cause, many U.S. cities see more days with heavy precipitation and increased risk of urban flooding, especially in areas where there are a lot of paved surfaces. 

Cities that experience less average rainfall can now expect to see heavier storms during their rainy season taxing a system that is used only rarely. With their antiquated capturing abilities, millions of gallons of precious water flow out of the community and into nearby surface waters. 

So what are we up against and how do we move forward?


98% of C40 cities reported that the anticipated effects of climate change present a significant risk to their city.


The National Flood Insurance Program is over $20 billion in debt.


In the U.S., floods caused 4,586 deaths from 1959 to 2005, while property and crop damage averaged nearly $8 billion per year (in 2011 dollars) over 1981 through 2011. The potential for increasing damages can only grow as climate change increases the frequency of extreme precipitation and amplifies the risk from expanded development.


Flash floods occur in small and steep watersheds and waterways, and they can be caused by short-duration intense precipitation events, dam or levee failure, or collapse of debris and ice jams.


Urban flooding is caused by short-duration, heavy precipitation events. Urbanization creates large areas of impervious surfaces, such as roads, pavement, parking lots, and buildings that dramatically increase runoff and reduce absorption of rainwater by natural surfaces.


Flash floods and urban flooding are directly linked to heavy precipitation and are expected to increase in the future.


Coastal flooding is predominantly caused by storm surges that accompany hurricanes and other storms.


Heavy precipitation events, historically occurring once every 100 years, are now projected to occur as frequently as every 5 to 15 years by late this century.


By 2050, more than 300,000 properties in the U.S., worth an estimated $136 billion today, could be rendered unusable by routine flooding.


9 of the costliest mainland U.S. hurricanes on record have occurred in the past 15 years.


Climate hazards are creating compounding effects. For example, sea-level rise amplifies storm surge, which may also grow due to increased wind and storm severity, exposing more assets to direct wave load damage.


Categorized succinctly, 7 main climate hazards exist:  tidal flooding amplified by sea-level rise; riverine and pluvial flooding; hurricanes/typhoons and storms; tornadoes and other wind events; drought; heat (temperature increases in both air and water); and wildfires.


100% of the 7 main climate hazards are tied to water.


By 2100, the Special Flood Hazard Area in the U.S. will increase 45% for riverine and coastal areas, assuming fixed coastlines.

The Greatest Regional Impacts of Climate Change in the U.S.

Northern and Southern Great Plains:

More extreme rainfall events will exacerbate water-related challenges in the Northern Great Plains.

Northeast and Southeast:

Much of the water infrastructure in the Northeast is nearing the end of its planned life expectancy. The combined effects of extreme rainfall events and rising sea levels are increasing flood frequencies, making coastal and low-lying regions highly vulnerable to the impacts of climate change.


Stormwater management systems and other critical infrastructure are already experiencing the impact from changing precipitation patterns and elevated flood risks.


Pacific salmon populations in the Northwest are directly affected by climate stressors. Low snowpack, decreasing summer streamflow, habitat loss, and increasing mortality due to warmer stream and ocean temperatures put further stress on their lifecycles.


Residents, communities, and their infrastructure, not to mention wildlife, continue to be affected by flooding and erosion of coastal and river areas, resulting from changes in sea ice.


Intensifying droughts, increasingly heavy downpours, and reduced snowpack combined with increasing water demands from a growing population, deteriorating infrastructure, and groundwater depletion reduce the future reliability of water supplies.


Since 1980, the U.S. has sustained 279 weather and climate disasters where overall damages/costs reached or exceeded $1 billion per event.

Billion-Dollar Weather and Climate Disaster Events in the United States

Figure 3.1: The figure shows (a) the total number of water-related billion-dollar disaster events (tropical cyclones, flooding, and droughts combined) each year in the United States and (b) the associated costs (in 2017 dollars, adjusted for inflation). Source: adapted from NOAA NCEI 2018.19


By the numbers: of the 279 disasters, we saw 18 wildfires, 28 droughts, 48 tropical cyclones, 126 severe storms, 33 flooding events, 17 winter storms, and 9 freezes.

Cumulative Costs of Sea Level Rise and Storm Surge to Coastal Property

Figure 8.1: This figure shows that cumulative damages (in 2015 dollars) to coastal property across the contiguous United States would be significantly reduced if protective adaptation measures were implemented, compared to a scenario where no adaptation occurs. Without adaptation, cumulative damages under the higher scenario (RCP8.5) are estimated at $3.6 trillion through 2100 (discounted at 3%), compared to $820 billion in the scenario where cost‐effective adaptation measures are implemented. Under the lower scenario (RCP4.5), costs without adaptation are reduced by $92 billion relative to RCP8.5 and are $800 billion with adaptation. Note: The stepwise nature of the graph is due to the fact that the analysis evaluates storm surge risks every 10 years, beginning in 2005. Source: adapted from EPA 2017.35


If no climate change adaptation actions are taken, cumulative damages to coastal properties in the U.S. are estimated to be $3.6 trillion by 2100.


Global sea levels have risen 10 inches since 1880. This does not include king tides or storm surges, but it makes them far more impactful.

Sea Level Since 1880


Nuisance flooding from sea level rise is 300% to 900% more frequent than it was 50 years ago.


Economic damage from water-related climate changes are estimated to total $684 billion annually by 2090.


Losses to the U.S. economy caused by hurricane winds and storm-related flooding are expected to cost $54 billion annually, equivalent to 0.3% of the nation’s current gross domestic product.


2017 was the costliest year on record for natural catastrophe events, with $344 billion in global economic loss, of which 97% was due to weather-related events.

The devastating toll of large floods on human life, property, environment, and infrastructure suggests that proactive management measures could minimize changing future flood risks and consequences.

Increasing heavy precipitation is an important contributing factor, but flood magnitude changes also depend on specific watershed conditions, including soil moisture, impervious area, and other human-caused alterations.


In some cases, it would save money for the government to buy flood-damaged properties, demolish them, and not rebuild on the land.


Flooding carries contamination and disease. Floodwaters can carry raw sewageleaked toxic chemicals, and runoff from hazardous waste sites and factory farms, as well as our own homes.


Flooding causes mental health problems, leads to economic loss (as in the form of lost businesses or wages), and uproots whole communities.

The Impact of Climate Change on Infrastructure

The U.S. is dealing with a significant shortfall in the spending necessary to maintain our existing stormwater and wastewater infrastructure. With increased demands from population growth, urbanization, and climate change, the costs will only increase. 

By properly maintaining our existing systems, we are able to optimize performance and determine point-by-point demands that can be mitigated by upgrades and retrofits.


Demand on U.S. treatment plants is expected to increase 23% by 2030. In order to manage this expansion of need, new treatment facilities must be constructed.


Failing to address aging and deteriorating infrastructure is expected to cost the U.S. GDP as much as $3.9 trillion (in 2015 dollars) by 2025.


Infrastructure age and disrepair make failure or interrupted service from extreme weather even more likely.


However, there are no common design standards or operational guidelines that address how infrastructure should be designed and operated in the face of changing climate risk, or that even target the range of climate variability seen over the last 50 years.


Infrastructure design is based on Intensity-Duration-Frequency (IDF) curves but doesn’t factor in changes in climate.


When rainwater surges, combined sewer overflows result. In many cases, these systems are already straining under the load of societal growth, which reduces tolerance for climate hazards and increases their vulnerability.


The more than 60,000 miles of U.S. roads and bridges in coastal floodplains are already demonstrably vulnerable to extreme storms, hurricanes, and flooding that cost billions in repairs.


Under-maintained infrastructure can lead to urban flooding.


Infrastructure is expected to bear the brunt of anticipated climate change adaptation costs, typically estimated to be between 60 and 80 percent of total climate change adaptation spending globally. That would average between $150 billion to $450 billion per year on infrastructure by 2050.


Estimates vary significantly, but consensus puts adaptation spending for new assets at about 1 to 2 percent of total infrastructure spending a year.

Managing the Difference Between Stormwater and Wastewater

Stormwater is the number one cause of water pollution in urban areas, as well as the number one cause of urban flooding. Managing stormwater as a resource, instead of as waste, will be critical to developing effective policies for the health of our communities. To get there, we have to be proactive about addressing water issues as a whole.


The #1 concern routinely identified within the water sector is the renewal and replacement of aging water and wastewater infrastructure.


National price index for water and sewerage maintenance in the U.S. increased more than 5x to 550.7 from 2000 to 2018, compared to 100 in 1984.


State and local governments in the U.S. spend $50 billion each year managing their stormwater and wastewater systems.


Nearly 240 million Americans— 76% of the population— rely on the nation’s 14,748 treatment plants for wastewater sanitation.


More than 56 million new users will be connected to centralized wastewater treatment systems over the next two decades, requiring at least $271 billion to meet current and future demands.


39 states have one or more stormwater utilities and seven states have 100 or more stormwater utilities.


The number of communities with stormwater utilities or fees has grown from approximately 1,400 in 2013 to 1,600 in 2016.


There are currently 800,000 miles of public sewage pipes in the U.S.


There are currently 500,000 miles of private lateral sewers in the U.S.


On average, 75,000 sewage overflow events happen each year


Americans use 322 billion gallons of water per day; this is all released as sewage.


The average family of four uses 400 gallons per day.


There is currently a $105 billion investment gap in funding for wastewater infrastructure in the U.S.


Approximately 772 communities in the U.S. have combined sewage systems (CSO), where wastewater and stormwater drain into the same pipe system. 


For the 184 CSO communities that discharge CSOs in the Great Lakes Basin, there were 1,482 CSO events in 2014, discharging an estimated 22 billion gallons of untreated wastewater into the Great Lakes Basin.


Blockages within sewage systems lead to the possibility of sewage systems bursting in the middle of urban areas and all the associated health hazards.


The biggest threat to wastewater systems is flooding.


When Hurricane Sandy struck the eastern seaboard of the U.S. in October 2012, 11 billion gallons of sewage flowed into rivers, bays, and coastal waters.


In 2004, 1.8 million to 3.5 million Americans had infectious waterborne illnesses associated with swimming in sewage-contaminated coastal waters. This is likely an underestimate due to underreporting.


70% of sewage generated in high-income countries is treated, compared to only 8% in low-income countries.

The Current Landscape of Cities and Urban Ecosystems

Without cities, we wouldn’t have sewage or urban flooding. If we didn’t build communities along the coasts, storms and hurricanes wouldn’t cause billions in damage. However, we do. 

We need to recognize that our cities are part of the overall climate system governing the planet. If we work within that construct, we can solve extraordinary problems, now and in the future.


With rising sea levels, approximately $1 trillion in national wealth held in coastal real estate is at risk. The continued viability of coastal communities depends on coastal water, land, and other resources for economic health and cultural integrity.


Urban areas, where the majority of the U.S. population lives, are the source of approximately 80% of North American human-caused greenhouse gas (GHG) emissions, despite only occupying 1% to 5% of the land.


In 2015, nearly 275 million people (about 85% of the total U.S. population) lived in metropolitan areas, and 27 million (about 8%) lived in smaller micropolitan areas.


Metropolitan areas accounted for approximately 91% of U.S. gross domestic product (GDP) in 2015, with over 23% coming from the five largest cities alone.


As of 2013, coastal shoreline counties were home to 133.2 million people, or 42% of the population.


Recent economic analysis finds that between $66 billion and $106 billion worth of real estate will be below sea level by 2050; and $238 billion to $507 billion, by 2100.


81% of Americans live in coastal states; 40% live directly on the coast.


60 million Americans work in coastal watersheds.


The U.S. coastal economy accounts for $7.9 trillion of GDP annually.


Coastal shoreline counties produced 40 percent of the nation’s total jobs and contributed 46 percent of its gross domestic product.

Cumulative Costs of Sea Level Rise and Storm Surge to Coastal Property

Table 8.1: The coast is a critical component of the U.S. economy. This table shows U.S. employment, GDP, population, and land area compared to coastal areas as of 2013. “Coastal zone counties” comprise shore-adjacent counties plus non-shore-adjacent counties. For more complete definitions, visit Source Kildow et al. 2016.1


By 2050, more than 386,000 existing homes along the U.S. coast, worth a combined total of $209.6 billion (2018 dollars), are likely to be at risk of permanent inundation from sea level rise alone.


If sea levels rise as predicted by the year 2100, almost 300 U.S. cities would lose at least half their homes, and 36 U.S. cities would be completely submerged.


One in eight Florida homes would be underwater by 2100, accounting for nearly half of the lost housing value nationwide.


Almost 2.5 million homes—worth a combined $1.3 trillion—are at risk of being underwater by 2100.

Time for Investment in Climate Technology

This paints a pretty daunting picture of our future. And yet there’s so much hope! 

Governments, corporations, and startups recognize the scale of risk that we face:  for our water, for our critical infrastructure, and for our communities. Investors are beginning to recognize the necessity—and value—of funding climate change adaptation technologies. With a concerted effort and total dedication, we absolutely can make the changes and improvements necessary to get on the right track.


The growth of climate technology since 2013 has been sizable. There has been an increase of more than 3750% over a 7-year period (2013-2019).


Since the coronavirus pandemic hit, major firms have pledged billions of dollars, including Amazon’s $2 billion ‘Climate Pledge’ venture fund, Microsoft’s $1 billion Climate Innovation Fund, and Unilever’s €1 billion climate fund.


Startups from these initiatives will take time to reach scale. However, the startups creating the most impact in the current business cycle (over the next 5-7 years) will likely be those founded in the 2010s.



The reality is $60B in investment as of 2019 is not enough, given the scale of the challenge. We need more entrepreneurs, more investments, and more buy in to make this work.

Contact us to learn more about ways to track and prevent flooding and other stormwater issues in your area with our advanced climate technology solutions.