Special thanks to GigaClimate Advisor and our A&R Series author, Chris Mangieri
Climate volatility is causing increased frequency of stormwater flooding and sewage leakages across the UK and Europe - as water infrastructure struggles with reliability, can public health concerns and industrial demand for continuous, high volumes of freshwater mean the time is right for innovating our wastewater and stormwater systems?
đ§The Hidden Infrastructure Failing in Plain Sight
Todayâs wastewater and stormwater systems were built for a different climate. They were designed for predictable rainfall, steady water flow, and a known set of nutrients. But today, these systems are breaking in ways that carry significant economic and public health risks.
These failures can occur quietly over time or suddenly, with catastrophic effects. Heavy rainfall overwhelms treatment plants, forcing the discharge of untreated sewage. Inadequate stormwater systems cause streets and homes to flood, displacing communities and taking lives. Rising groundwater levels due to saltwater intrusion render below-ground septic tanks unusable. Every time this happens, it becomes clear that wastewater isnât just a utility and public health service; itâs a resilience system thatâs failing under aging and inadequate infrastructure amplified by climate pressures.
While wastewater failures are a massive global challenge, this article focuses primarily on the US market, using international examples to help illustrate the scale of the problem.
Globally, only 20% of wastewater is treated before being discharged, leaving the rest to flow into rivers, oceans, and groundwater untreated. Inadequate and unsafe sanitation accounts for 564,000 deaths globally each year, primarily in low- and middle-income countries. In 2000 in the US, storm events triggered 850 billion gallons of raw sewage overflows from combined sewer overflows (CSOs). This number has only increased with population growth and more frequent deluge events. In the UK, only 14% of rivers meet âgood ecological status,â and the EU is on track to pay at least âŹ440 billion (âŹ1.7 trillion in a worst-case scenario) to deal with pollution and health impacts associated with PFAS, âforever chemicals,â by 2020.
At the same time, the rapid buildout of AI data centers and semiconductor manufacturing is reshaping water demand. These facilities are among the most water-intensive industrial usersââit takes 4m3 of feedwater to make 1m3 of ultrapure water for chip manufacturingââwith 29% of fabrication plants already located in extremely water-stressed regions.
These arenât edge cases; theyâre systemic signals. Every untreated gallon downstream increases pressure upstream; on freshwater supplies, ecosystems, public health, and infrastructure already under strain. This isnât just about fixing sewer and stormwater systems. Itâs about closing the loop in a world where linear water systems no longer work.
đ The Four Wastewater Worlds
To understand where founders can build, we first have to disaggregate the problem. Wastewater isn't one systemââit's four. Municipal, rural, agricultural, and industrial wastewater each has distinct failure points, regulations, and climate vulnerabilities that vary even further by region. Innovation only becomes possible once theyâre separated with defined failure points and an understanding of why the market is underserved.
đď¸ Municipal systems are the most visible layer of wastewater infrastructure,
and some of the most vulnerable to climate disruption. In older cities across the Midwest and Northeast, stormwater and sewage often share the same pipes. When heavy rainfall hits, these CSOs dump untreated waste into local waterways. In 2018, Milwaukeeâs wastewater system experienced 6 CSO overflows, releasing more than 1.2 billion gallons of stormwater and untreated wastewater into Lake Michigan, despite its advanced deep tunnel systems, which were built to prevent such overflows. 60% of New York City has a CSO system that discharges roughly 18 billion gallons across 398 outfalls each year. During CSO events in the Harlem River, nitrogen and phosphorus levels can jump to 5x to 8x higher than what regulators consider safe, with ammonia concentrations measured at 2.7 mg/L and phosphorus at 0.20 mg/L, levels known to fuel algal blooms and strip oxygen from rivers and lakes.
Compounding this challenge, stormwater systems themselves are increasingly overwhelmed. Pipes and drainage networks designed for lower-intensity rainfall now struggle to handle todayâs deluges, turning heavy rain into a direct driver of infrastructure failure.
Most municipal treatment plants were also never designed to remove emerging contaminants such as pharmaceuticals, PFAS, and microplastics. Retrofitting plants with advanced or tertiary treatment (i.e., activated carbon, advanced oxidation, and membrane systems) is technically feasible but prohibitively expensive, leaving cities with few options. It can cost between $2.7 and $18 million per pound to remove and destroy PFAS from municipal wastewater, while PFAS can be purchased for as little as $50 to $1,000 per pound. New short-chain PFAS are up to 70% more expensive to remove and destroy.
Circularity failure: Untreated water is often discharged during storm events, with a loss of water and nutrient reuse potential. At the same time, legacy plants cannot economically remove emerging contaminants, sometimes blocking reuse entirely.
Why this market is underserved: Political constraints, slow procurement, and capital-intensive retrofit paths leave cities unable to adopt modular or affordable solutions, especially for overflow control and advanced treatment.
đž Rural wastewater failures are quieter
but no less dangerous, with 3.4 billion people (2 in 5) globally still lacking access to safe sanitation. In the US, millions of homes (20-25% of households) in rural communities rely solely on antiquated cesspools and septic systems that werenât designed for modern housing densities, climate volatility, and preventing nutrient discharge. In Alabamaâs Lowndes County, residents have lived with raw sewage in their yards for years due to failing septic tanks, compounded by high water tables and poor soils. Hookworm, a parasite transmitted through untreated wastewater that was once thought to be eradicated in the US, has re-emerged and is present in 34.5% of stool samples from Lowndes County residents. Globally, the picture is worse. In flood-striken regions across Nigeria, Pakistan, and, recently, Chad, pit latrines and open defecation sites remain common. When extreme weather inundates them, local drinking water is contaminated, and disease outbreaks occur.
Circularity failure: Waste that should be confined and treated instead seeps into soils and aquifers, returning nutrients and pathogens directly to drinking water sources rather than being safely captured or recovered.
Why this market is underserved: Rural sanitation lacks a centralized utility, a stable tax base, or legacy infrastructure for retrofitting, leaving conventional wastewater models economically unviable.
đ˝ Agricultural wastewater is often invisible to the public
until climate stress exposes it. Animal manure lagoons and runoff systems were designed for steady rainfall, not the volatile climate now defining modern agriculture. Extreme storms can breach lagoons and flush nutrients off fields, while droughts can concentrate nitrogen and phosphorus in soils and waterways. During Hurricane Florence in 2018, more than 30 hog waste lagoons in North Carolina were breached, spilling untreated manure into rivers and fields that supply drinking water to nearby communities. According to the USGS, agricultural runoff is now the largest source of excess nutrient loading in the US, contributing over 70% of nitrogen and phosphorus loads in the Gulf of Mexico. The economic cost is significant, with nutrient freshwater pollution costing at least $2.4 billion annually (in 2015 dollars) in the US. In Europe, similar dynamics are playing out, despite the Nitrates Directive; compliance remains uneven, with regions like the Netherlands and Spain delaying implementation and exceeding discharge limits, driven by pushback from local farmers.
Circularity failure: Nitrogen and phosphorus worth billions in annual input costsââa $145 billion global marketââare washed off farms during floods or concentrated during drought, exporting valuable nutrients as pollution instead of recovering them.
Why this market is underserved: Agricultural wastewater can be diffused, episodic, and politically sensitive, with limited oversight and few practical delivery models that fit farm operations. This leaves nutrient recovery and runoff control largely unaddressed despite mounting downstream costs.
đ Industrial wastewater brings a different kind of risk:
high toxicity, high liability, and rapidly tightening regulations. Globally, industry accounts for just under 20% of freshwater withdrawals and generates billions of gallons of wastewater daily, often containing solvents, heavy metals, PFAS, and pharmaceutical residues that conventional treatment plants canât and were never designed to remove. The result is growing exposure on both sides of the pipe. In low-regulation regions such as Hazaribagh, India, leather tanneries discharged chromium-laden wastewater directly into open canals as recently as 2017, contaminating local waterways. But even highly regulated regions have issues. In 2022, a suspected industrial discharge into the Oder River in Europe killed more than 1,000 tons of aquatic life, triggering emergency monitoring and new enforcement protocols. As drought tightens industrial water access and PFAS rules expand globally, manufacturers are facing a new reality: advanced treatment and on-site reuse are no longer optional compliance upgrades, but core infrastructure for operational continuity.
Circularity failure: Industrial process water is treated as a disposable liability rather than a recoverable asset, with persistent contaminants preventing reuse and pushing valuable water, energy, and materials downstream, rather than closing on-site loops.
Why this market is underserved: Legacy treatment options are either bespoke and capital-intensive or designed for municipalities, leaving mid-market industrial operators without modular, affordable solutions as regulations tighten and water scarcity turns compliance into an operational risk.
đ° Climate Stressors & Wastewater Failure Modes
Climate stressors are changing how systems break. For founders, the opportunity is in understanding these failure modes not as freak events, but as the new normal to design and build around.
Hereâs how climate stressors are showing up across the wastewater stack:
Flooding breaches manure lagoons, overwhelms septic systems, and inundates municipal treatment plants, especially in low-lying and coastal areas. In industrial zones, floodwaters can mobilize stored chemicals and contaminated sediments, spreading pollution beyond facility boundaries.
Drought reduces flows to wastewater treatment plants, triggering sewer backups and concentrating ammonia, nutrients, and pathogens in municipal and rural systems. In agricultural regions, drought intensifies nutrient buildup in soils and waterways, while industrial facilities face rising pressure to reuse water just as treatment margins tighten.
Thermal stress disrupts biological treatment processes, accelerates odor and biosolid instability, and can increase the need for chemical treatment. Municipal plants can lose process efficiency, while agricultural lagoons and industrial basins experience heightened biological and chemical volatility.
Power loss shuts down pumps, lift stations, aeration, and process controls. For systems that lack adequate redundancy, short outages can lead to costly, prolonged sanitation failures. Industrial facilities dependent on continuous treatment can face production shutdowns or uncontrolled discharges.
Storm surge and saltwater intrusion corrode infrastructure, damage treatment biology, and permanently alter influent chemistry. Coastal municipal plants lose biological performance, agricultural soils become salinized, and industrial pretreatment systems struggle outside their design tolerances.
These failure modes fall into two reinforcing categories:
Acute: sudden events like hurricanes, flash floods, and storm surge that trigger visible system collapseââlagoon breaches, septic failures, treatment plant overflows, and industrial releases.
Chronic: long-term stressors such as rising groundwater, sustained heat, salinity intrusion, persistent chemical accumulation, and prolonged underflow in drought-prone regions that quietly degrade system performance.
đˇââď¸ Where Founders Can Build: Market Opportunities in Wastewater and Reuse
Across all four wastewater worlds, the pattern is similar: infrastructure built for stability fails under volatility. Each stressor exposes the limits of centralized, energy-intensive systems and creates demand for modular failover, passive treatment layers, off-grid autonomy, and remote diagnostics. This is where climate adaptation becomes infrastructure resilience, and where the solution stacks that follow begin to take shape.
đ Wastewater Solution Stacks: Where Urgency & Dollars Converge
Wastewater isnât just under pressureâitâs underpriced. The average US household pays about $780 per year for wastewater treatment. Residential customers pay roughly $9.09 per 1,000 gallons, commercial customers $7.23, and industrial users even less, unless they trigger surcharges, which can effectively subsidize high-load dischargers. In many rural areas, wastewater isnât priced at all.
For decades, most US wastewater systems were built with federal funding under the Clean Water Act to the tune of $650 billion. That support has largely vanished. The federal share of wastewater capital investment has fallen from 63% in 1977 to just 9% in 2017, leaving utilities, landowners, and operators to absorb rising climate and regulatory risk. The gap between what systems cost to operate under climate stress and what users actually pay is widening.
That mismatch is where opportunities exist for founders. Each wastewater world fails differently, but the solution stacks gaining traction share three traits: modular deployment, low energy intensity, and the ability to be installed without waiting on billion-dollar public works projects. Where those stacks intersect with underpricing and regulation, real markets are already forming.
đď¸ Municipal Systems: Smart Overlays for CSO Risk
Municipal wastewater systems are primed for overlays and add-ons, not rebuilds. US wastewater infrastructure earned a D+ from ASCE, with many plants operating beyond design life. That pressure is driving demand for CSO risk and sewer overflow technologies. Sensor networks, real-time flow control, AI optimization, and automated gates are being procured now to reduce overflows and defer capital-intensive projects. In South Bend, Indiana, smart sewer systems reduced CSO volumes by up to 70%, avoiding more than $500 million in tunnel construction costs.
At the same time, PFAS is turning biosolids from a desired farmfield additive into a toxic long-term liabilityââone fifth of all US agricultural land may be contaminated with PFAS. Conventional treatment doesnât destroy PFAS, rather it concentrates it in sludge. In response, some states like Maine have halted land application altogether. New solutions, such as high-temperature pyrolysis and gasification, are emerging to destroy PFAS in biosolids rather than displacing it downstream.
The opportunity is clear: software overlays upstream, paired with targeted PFAS destruction and residual management downstream, that preserve treatment capacity, can be deployed quickly, and fit within utility budgets.
đž Rural Systems: Off-Grid Service at the Edge
Rural wastewater doesnât need extension; it needs autonomy. In low-density areas, the cost of extending centralized sewer systems often exceeds what communities can afford to build or maintain. This is creating demand for new off-grid, containerized treatment systems that donât need constant monitoring and service. In Alaska, portable alternative sanitation systems have replaced the âhoney bucketâ model entirely (five-gallon buckets with trash bags that are brought to landfills), delivering reliable service and clean water without the need for buried infrastructure. The systems can be deployed incrementally and moved as demand changes.
Here, founders win by delivering reliable sanitation with minimal operations, supported by Justice40 funding, USDA rural water loans, and EPA access-gap programs.
đ˝ Agricultural Systems: Nutrient Recovery and Runoff Verification
Agricultural wastewater offers one of the clearest circularity plays. Floods and storms wash nutrients off farms, yet those same nutrients remain valuable inputs if retained and recovered. In animal agriculture, covered anaerobic lagoons and digesters can concentrate nutrients while destroying pathogens, reducing methane emissions, and generating baseload regional powerâUS manure-based digesters produced roughly 3.39 million MWh of power in 2023. In crop agriculture, edge-of-field wetlands and saturated buffers can reduce nitrate concentrations in runoff by up to 91%.
At the field level, soil-retention tools from cover crops to emerging bio-based hydrogels, particularly in high water-stressed areas, can further reduce nutrient losses by slowing water movement and improving root-zone uptake during both droughts and deluges. These tools complement downstream recovery systems by reducing runoff volumes and stabilizing nutrient flows.
The opportunity is a nutrient recovery stack that prevents losses, captures nitrogen and phosphorus, verifies performance, and returns value to the farm without disrupting the growing season.
đ Industrial Systems: Pretreatment, Reuse, and Recovery-as-a-Service
Industrial wastewater is no longer just a compliance issue; itâs an operational risk and chemical liability. PFAS regulations have expanded rapidly throughout the EU, while the US is still playing catch-up, with treatment requirements only set to take effect in 2031. Many industrial systems were never designed to remove persistent contaminants, leaving operators exposed as regulations tighten.
The direction of travel is clear. Hyperscalers like Google, Microsoft, and Amazon are already deploying advanced reuse at data centers in water-stressed regions, treating water as mission-critical infrastructure. But there is still significant opportunity for hyperscalers and semiconductor manufacturers to partner with municipalities to increase water utility efficienciesââ21% of water withdrawals are lost to leakages and inefficiencies globallyââand utilize municipal wastewater as an input.
The larger, less-served market lies below these large players: mid-market manufacturersâfood processors, metal finishers, specialty chemical plantsâface tighter discharge limits and emerging contaminant exposure (e.g., PFAS), but may lack the upfront capital or teams to implement needed systems.
This is where compliance and recovery-as-a-service models are taking hold. Companies like Aquacycl exemplify this shift, providing modular on-site systems that treat high-COD industrial wastewater, reduce sludge, and convert organic waste into usable energy. All the while, without requiring operators to own or run complex infrastructure. Customers contract for outcomes: water treated to spec, residuals reduced, and compliance risk shifted off-balance-sheet. These models are increasingly financeable and are being accelerated by the $11.7 billion Clean Water State Revolving Fund funding.
Across all four wastewater worlds, the pattern is consistent. Wastewater is undervalued, overburdened, and exposed to climate stress. Solutions that are cheaper to operate, modular to deploy, and capable of deferring capital-intensive retrofits are no longer optional; theyâre necessary for the market.
đ A Call to Builders: Wastewater Is Ready
Wastewater is no longer a forgotten back-end service. Itâs frontline resilience infrastructure.
Itâs what keeps pathogens out of groundwater after floods, holds nutrients on farms during deluges, and keeps factories running during drought. In a climate-stressed world, wastewater systems are the keystone for turning a linear water economy into a circular one.
At GigaClimate, we see wastewater as a significantly overlooked opportunity in climate adaptation and resilience. It touches every systemâurban, rural, agricultural, and industrialâyet remains underbuilt, underpriced, and under-innovated.
We see wastewater as adaptation infrastructure, built to absorb climate shocks; continuity infrastructure, designed to fail softly rather than catastrophically; and recovery infrastructure, capturing water, energy, and nutrients instead of losing them downstream.
If youâre building in this space, we want to hear from you. GigaClimate is actively sourcing and supporting founders turning climate stress into resilient infrastructure.
This is where the crisis meets the overlooked system. Letâs build what comes next.
This is a great essay! I think this aspect of climate change is often side-stepped or ignored from a public perspective. This isn't intentional, but it is how things are typically framed. From a media standpoint, water treatment isn't sexy and likely won't generate enough clicks. It is unfortunate though because this merits serious discussion.
I also like the potential solutions you run through. One I have looked at myself is methane digesters. I think they are an excellent method for water treatment, energy production, and creation of fertilizer.
One major aspect of water treatment also involves the potential of rewilding lands. This would create more absorptive soils to mitigate some issues of flooding. It wouldn't be a way to completely solve the problem as high concentration of precipitation will likely overwhelm soil absorption. But at least it would mitigate some of the issues we're seeing with weakened topsoil and increased erosion without strong root systems.
Another benefit of rewilding would be the potential to improve estuaries or salt marshes which can act as a natural zone for filtration, but this would require reduction of industrial waste accumulation.
There is no easy solution here...