Aging infrastructure, extreme weather, and pollution: Why drinking water is under pressure

Pennsylvania’s century-old water infrastructure faces modern climate threats. Here’s why it’s complicated.

The U.S. has over 2 million miles of underground pipes controlled and run by about 150,000 public water systems. These public systems serve about 90% of the population, while approximately 10-15% use private wells.

As the Philadelphia region was being built over 250 years ago, the water infrastructure consisted of wooden logs and gravity. With limited knowledge of how disease spread, there were few protections or treatments for drinking water.

As our city and suburbs have evolved, how we get and treat our drinking water has also changed. And though we have a much better grasp on handling it, our water and its sources face new threats.

Why fixing our water systems won’t happen overnight

Our water infrastructure which stores, transports, treats, and distributes water, is showing its age. Some of these pipes were laid nearly 75 to 100 years ago, which is about the length of the average pipe’s lifespan. Other aspects of the system are even older. Approximately 30% of Philadelphia’s water mains – an underground distribution system that brings water from a treatment facility to your home, school, or workplace – were installed before 1900.

The aging water infrastructure is partially why the American Society of Civil Engineers’ 2025 Infrastructure Report Card, a comprehensive assessment of the nation’s water, bridges, and roads, gave the country a C- for drinking water infrastructure and a D+ for wastewater infrastructure.

In 2023, Pennsylvania was listed by the Environmental Protection Agency (EPA) as one of the states with the greatest need for water infrastructure updates in the next 20 years, with an estimated needed investment of $24.30 billion.

Another issue is lead, which was the preferred material for water piping for decades because it was heat-resistant and durable. Over 70% of US cities used lead piping by 1900, and it wasn’t federally banned until 1986. Although we now know that there is no safe level of lead exposure, (which can cause various illnesses including damage to the kidneys, developmental delays, and infertility) millions of homes are left with lead piping.

Though there have been movements to replace these pipes, Pennsylvania remains one of the top offenders. The state has the fourth-highest number of lead service lines, with almost 700,000 (or 7.5% of all service lines in the state) counted in 2023 by the EPA. Although the ownership of the lines may vary by systems, homeowners are generally responsible for their service lines from the curb valve to the water meter and the utility company from the water main to the curb valve, according to the EPA.

Replacing and updating water systems carries a hefty price tag. Utilities across the country have had to raise household water bills by roughly 64% from 2012 to 2023, primarily due to increased labor and inflation.

But this work is not as simple as shutting everything down and starting over. Water treatment plants and distribution systems must continue operating while repairs and upgrades happen in phases, a logistical challenge when communities rely on safe running water every day.

“When we add capacity, or when we change things at the plant, we must keep everything else running, said Eric Damon, manager of Aqua’s Crum Creek and Ridley Creek Treatment Plants. “We can’t just say, ‘We need to replace a whole bunch of pumps. Let’s shut the plant down for a month, two months, or longer.’ We can take short shutdowns, and we have to move a lot of water around to do that.”

How climate change is complicating our waterways

These infrastructure woes are complicated by the increase of rain, snow, storms and drought due to climate change. As this past year has shown, drought stresses water systems because it depletes surface and groundwater sources and leads to water quality challenges. In turn, utilities are forced to implement usage restrictions and adjust certain treatments to maintain water quality. With water conservation top of mind, utilities are focused on replacing aging infrastructure to cut down on wasteful leaks and help maintain service reliability.

While we have seen recent drought periods, the overall rain amount during the heaviest downpours in the Northeast has actually increased by about 60% since the 1950s, the biggest increase in the nation. And with more rain during those storm events, there is a higher risk of flooding, which increases the contamination risk and threatens to overwhelm the outdated infrastructure. When Hurricane Ida swept through Pennsylvania in 2021, flooding I-676, regional water treatment plants like the Belmont Water Treatment Plant and Pickering West were affected. Water suppliers had to be nimble to keep residents in service, and many suffered costly damage. The storm illustrates the flooding risk to treatment plants, many of which are located along rivers as the source of our drinking water.   

More rain and flooding also increase the risk of washing sewage and other pollutants, into drinking water sources. One contaminant of concern is PFAS, or per- and polyfluoroalkyl substances, human-made chemicals found in everything from watchbands to dental floss to water. They have been termed “forever chemicals” because they cannot break down naturally, and they can lead to health concerns such as increased cancer risks, pregnancy issues, and reduced immune response. As EPA regulations are in flux with the Trump Administration, water suppliers have been actively working to remove PFAS from drinking water with costly treatment upgrades.

More precipitation during winter means more snowfall, and road salt. The US uses about 15-32 million metric tons of road salt – approximately double the usage from 1975 – and studies show that nearly all of it enters rivers, streams, and aquifers. Over the years, there have been higher levels of sodium and chloride in our drinking water sources.

“If we don’t do something, if we don’t use less [road salt], it will continue to increase,” said Dr. John Jackson, senior research scientist at Stroud Water Research Center to Green Philly. “All we’re doing is swapping fresh water for salt water.”

The salt can corrode drinking water infrastructure, hurt private wells, and is nearly impossible to get rid of, since it doesn’t evaporate or filter out. This is especially a concern for residents on a salt-restricted diet.

“A ton of road salt costs about $100,” Dr. Jackson said. “It causes about $3,000 in infrastructure damage. The environmental effects: it changes the soil, changes the water, and it changes what lives in the water.”

As summer temperatures rise and growing season ramps up, what residents put on lawns and farmland also affects waterways. Fertilizers, manure, yard and pet waste can run off into waterways, spreading pathogens and leading to nutrient pollution that can cause cyanobacteria or harmful algae blooms. Those toxin-producing blooms can be harmful to animals and humans and cause problems for drinking water treatment.

An unexpected adversary: time

As water rushes down rivers and creeks over decades, the banks erode, exposing soil and root structures. Anything in that soil enters the waterways as well, and without robust streamside forests to stabilize the banks and filter stormwater, pollution continues unchecked.

That material, called sediment, not only impairs water and habitat quality, but it fills in reservoirs, reducing storage capacity that is meant to ensure ample drinking water- another costly maintenance problem for water utilities. That sediment often carries excess nutrients into the reservoirs as well, leading to a proliferation of algae that can affect the taste or smell of drinking water.

So, what can we do?

The numerous threats to our drinking water can seem daunting. But the good news is that our understanding of water challenges is greater than ever, leading to the development of modern treatment and protection practices.

In the coming weeks, Green Philly will take readers behind the scenes of how drinking water is protected and explore the challenges and solutions shaping the future of clean water.

This is a three-part series about our drinking water, presented by Aqua, an Essential Utilities company. Join us over the coming weeks to learn where your water comes from, how it’s protected, what it goes through before it reaches your tap, and what actions you can take at home.

Cover photo: Unsplash