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CFR Investigation Team
For ninety years, Chicago's building code required every home to be connected to the water system through a lead pipe. The city mandated the poison.
Today, roughly 400,000 of those pipes remain in the ground — more than any other city in America. More than the next several largest cities combined. Half of all water connections in Chicago flow through lead.
The fix is simple: dig up the lead pipe, replace it with copper. Newark, New Jersey replaced all 18,000 of theirs in three years for $120 million. The federal government has billions available for exactly this purpose.
Chicago chose a different path. Instead of replacing the pipes, the city pumps orthophosphate — a chemical that coats the inside of lead pipes with a protective mineral layer — into every gallon of water it delivers. The cost? $388 million for a single three-year contract with one chemical company in Peru, Illinois. That's roughly $129 million a year, up from $2.5 million a year just five years ago.
The problem isn't the chemistry — orthophosphate does provide better corrosion protection than what Chicago used before. The problem is that nobody asked whether a 50-fold cost increase was the right use of resources for a city that was already in compliance and should have been replacing pipes all along. The Illinois EPA mandated the switch without publishing its analysis. The city accepted the bill without demanding to see the math. And there is still no plan to make this spending temporary.
Without that plan, $129 million a year isn't a bridge. It's a toll road with no exit.
This is a story about what happens when the people running a city stop understanding how it works.
Chicago didn't just allow lead pipes. It required them.
From approximately 1897 until 1986, Chicago's municipal building code — Chapter 18-29-605 of the plumbing provisions — mandated that water service lines be made of lead. Every home, apartment building, school, and business constructed during those ninety years had a lead service line installed by law.
The rationale was practical, not malicious. Lead was durable, malleable, and cheap. It could bend without breaking, lasted decades, and was the standard plumbing material of the era. The word "plumbing" itself derives from the Latin plumbum — lead.
In 1986, Congress passed the Safe Drinking Water Act Amendments banning lead pipes and lead solder in public water systems. Chicago's code was updated. But the 400,000 pipes already in the ground stayed there.
Five years later, in 1991, the EPA issued the Lead and Copper Rule — the first federal regulation requiring utilities to test for lead at the tap and take action if levels exceeded 15 parts per billion. Chicago added blended phosphate to its water, passed its tests, and declared the problem managed.
It wasn't managed. It was hidden.
There is no safe level of lead exposure. The CDC eliminated its "level of concern" in 2012 because the science is unambiguous: even low-level lead exposure causes measurable, irreversible harm.
Nationally, lead paint remains the largest source of childhood lead exposure. But the EPA estimates that drinking water accounts for 20% or more of a person's total lead exposure — and for formula-fed infants, whose primary nutrition is mixed with tap water, that figure rises to 40-60%. For Chicago's youngest residents, the pipes are the primary threat.
In children, lead exposure causes:
A 2024 study published in JAMA Pediatrics analyzed over 38,000 household lead tests collected in Chicago between 2016 and 2023. Using machine learning to model citywide exposure, the researchers estimated that 68% of Chicago children under six — approximately 129,000 kids — are exposed to lead-contaminated drinking water. The study also found stark racial inequities: majority-Black and Hispanic neighborhoods had higher exposure rates and lower testing rates.
The city's official monitoring tells a different story. Chicago samples approximately 50 homes to assess a system with 400,000 lead service lines — the reduced monitoring minimum under EPA rules. The standard requirement is 100. Chicago earned its reduced status by consistently passing tests using the very phosphate treatment now in question. Those utility-selected sites report 90th percentile levels of 8-10 ppb, below the action level. The question is whether 50 homes can tell you anything meaningful about 400,000.
Put the IQ numbers in economic terms: each IQ point lost to childhood lead exposure reduces lifetime earnings by approximately $31,000 in 2024 dollars (inflation-adjusted from Grosse et al., 2002, Environmental Health Perspectives, which estimated ~$17,815 in 2002 dollars). With 129,000 children exposed, even a conservative one-point average IQ loss represents $4 billion in lost lifetime earnings — for a single year's cohort. Every year the city delays, it creates a new one.
Blood lead data from the Chicago Department of Public Health shows dramatic overall improvement over decades — but persistent geographic and racial disparities. South and West Side neighborhoods — Englewood, Austin, Lawndale, Humboldt Park — show rates of elevated blood lead levels 2-5x higher than North Side areas. The zip codes with the most lead pipes are the zip codes with the most lead-poisoned children.
🔬 The Science: Why Low Doses Are Worse Per Unit The Lanphear meta-analysis (2005, Environmental Health Perspectives) — the most comprehensive study of lead and IQ to date — found something counterintuitive: the steepest IQ decline occurs at the lowest blood lead levels. The dose-response curve is supralinear — meaning the first few micrograms per deciliter of blood lead cause more damage per unit than higher levels.
A child going from 1 µg/dL to 5 µg/dL loses more IQ points than a child going from 15 µg/dL to 19 µg/dL. The damage is front-loaded. This means there is no "safe" low level — and it means that the modest lead levels found in Chicago tap water (consistently detectable, rarely dramatic) are hitting children in the range where each microgram does the most harm.
Lead doesn't come from Lake Michigan. The water leaving Chicago's treatment plants is clean. The contamination happens between the plant and your glass, inside the infrastructure.
A lead service line is the pipe — typically half-inch to three-quarter-inch diameter, made of pure lead — connecting the water main under your street to your home's internal plumbing. When water sits in contact with lead, the metal dissolves. How fast depends on chemistry — and the conditions are often worst when you need the water most.
And there's a critical factor most people don't know about: galvanic corrosion. When a new copper pipe meets an old lead pipe, a chemical reaction actually makes the lead dissolve faster — which is why partial pipe replacements, where the city replaces its portion but the homeowner's side stays lead, can actually increase lead levels. You've created a fresh lead-copper junction with no protective coating.
This is why the EPA's 2024 Lead and Copper Rule Improvements now require full-line replacement — both the city's side and the homeowner's side. Partial replacements do more harm than good.
🔬 The Science: Why Two Metals Are Worse Than One When a lead pipe connects to a copper pipe, the two metals create an electrochemical cell — essentially a weak battery. Lead is more reactive (anodic) than copper, so it corrodes preferentially: lead atoms dissolve into the water while the copper is protected. The voltage difference is about 0.47V — small, but persistent. Every hour water sits in that junction, lead accumulates.
Other factors compound the problem. Below pH 7, lead dissolves roughly ten times faster than at pH 8. Hot water leaches more lead than cold. And stagnation time matters enormously — water sitting overnight in a lead pipe accumulates lead with every passing hour. This is why the standard advice is to run your tap for 30 seconds to two minutes each morning before drinking.
The most common approach to managing lead in water isn't removing the lead. It's coating it.
Orthophosphate is a simple inorganic ion added to treated water. It reacts with dissolved lead to form a dense, insoluble mineral coating on the interior surface of lead pipes. If maintained continuously — meaning phosphate is added to the water every day, forever — it works. Lead levels drop. Tests pass.
The coating — a mineral called hydroxypyromorphite, so insoluble it makes table salt look like sugar in hot coffee — is genuinely effective chemistry. The problem isn't that it doesn't work. The problem is that it has to work forever.
For decades, Chicago used a blended phosphate — a mix of polyphosphate (a sequestrant that keeps the water clear) and orthophosphate (the active corrosion inhibitor). It was cheap. It worked well enough. The city consistently tested below the EPA's action level of 15 parts per billion.
Then, in Spring 2024, the Illinois EPA directed Chicago to switch to 100% orthophosphate. On paper, it provides more effective corrosion protection. But even taking the city's own testing at face value — 50 homes, utility-selected — Chicago was in compliance. The switch wasn't triggered by a failure. It was anticipatory.
Pure orthophosphate requires significantly higher doses. Higher doses times the massive volume of water Chicago delivers — 5.3 million people across the city and 125+ suburbs — means exponentially more chemical. The cost went from $2.5 million a year to $129 million.
Was this the sensible allocation of resources for a city that should be removing those pipes, not investing in a more expensive coating for them? The IEPA has not made public the cost-benefit analysis behind the directive. We could not locate a public comment period in the Illinois Register. No one in city government appears to have questioned whether the money might be better directed toward replacement. They accepted a 50-fold cost increase without demanding to see the work.
What we do know is the cost. Carus Corporation, a 110-year-old chemical company based in Peru, Illinois, has held Chicago's phosphate contracts since a pilot program in 1997, with the first major supply contract beginning in 2002. They won a $9.4 million sole-source bridge contract in July 2024 to cover the transition, followed by the $388 million contract in November 2024.
We have not been able to locate a formal public rulemaking document for the IEPA's orthophosphate directive, nor the corrosion control study that informed it — if one exists. The federal Lead and Copper Rule Improvements require "optimal corrosion control treatment" but don't prescribe a specific chemical. Illinois went further. These are questions worth FOIAing.
Carus may well be the best or only supplier at this scale. That's not the scandal. The scandal is that the city needs this contract at all — because it didn't spend the last thirty years replacing the pipes.
| Period | Total Contract | Annual Cost | Procurement | Chemical |
|---|---|---|---|---|
| 1997-2001 | $0 | $0 | — | Corrosion control (pilot) |
| 2002-2007 | $12,000,000 | $2,400,000 | Bid | Blended phosphate |
| 2008-2013 | $27,000,000 | $4,900,000 | Bid | Blended phosphate |
| 2013-2021 | $20,000,000 | $2,500,000 | Bid | Blended phosphate |
| Jul 2024 | $9,400,000 | $9,400,000 | Sole source | Orthophosphate (bridge) |
| 2024-2027 | $388,000,000 | $129,000,000 | Bid | 100% orthophosphate |
| Total | $456,400,000 |
Source: Chicago Data Portal, Contracts dataset (rsxa-ify5). Carus Corp / Condy Holdings LLC dba Carus LLC, Peru, IL.
Since the Lead and Copper Rule took effect in 1992, Chicago has replaced approximately 14,000 lead service lines out of 400,000. That's 3.5% in thirty-three years.
For most of that period, the city replaced pipes only when they broke or when streets were torn up for other utility work. There was no proactive replacement program. Under Mayor Emanuel, the city took limited steps — free testing kits and a real estate disclosure ordinance — while simultaneously disturbing thousands of lead service lines through an aggressive water meter installation program that lacked adequate safeguards. Under Mayor Lightfoot, a pilot program launched.
Under Mayor Johnson, the pace has accelerated meaningfully — roughly ten times the historical average, to approximately 4,000-5,000 replacements per year. That's real progress and deserves credit. But the math is unforgiving: even at 5,000 per year, the job takes 80 years. The federal deadline is 10. That means 40,000 pipes per year — eight times the current pace.
In 2019, Newark, New Jersey had 18,000 lead service lines and a crisis — lead levels spiking above EPA action levels after a corrosion control failure. The city distributed bottled water. Headlines compared it to Flint.
Three years later, every lead service line in Newark was replaced. All 18,000. Total cost: approximately $120 million, or about $6,700 per line. The city used state bonding and federal grants. Residents paid nothing.
Chicago's current replacement cost is $35,000 per line — 5.2 times Newark's. The city attributes the difference to dense urban construction, deeper frost lines, split public/private ownership, and one-off rather than block-by-block replacement. But those explanations don't fully account for a 5.2x gap. Newark is also a dense, old northeastern city with complex infrastructure. The difference is primarily one of approach: Newark committed to an aggressive block-by-block timeline with dedicated crews. Chicago has been doing piecemeal replacements for decades.
Let's be honest about scale: Chicago has twenty-two times more lead pipes than Newark had. This is not an apples-to-apples comparison. Even at double Newark's per-line cost — accounting for Chicago's greater scale and complexity — full replacement would run $5-6 billion. At $20,000 per pipe — Chicago's own block-by-block estimate — the total is $8 billion. That's a staggering number. But as we'll show, it's still less than the cost of coating those pipes with chemicals forever.
So what could have been done? If Chicago had started replacing lead service lines at a serious pace — about 6,000 per year — beginning in 2015, even at $15,000 per line (roughly double Newark's cost, accounting for Chicago's complexity), the city would have replaced approximately 60,000 pipes by now for about $900 million. Instead, it replaced about 10,000.
If Chicago had started in 2002, when the first major Carus phosphate supply contract began, the city could have replaced over 138,000 lines — more than a third of the total — for about $2 billion at that same $15,000 rate. During that same period, Chicago spent roughly $59 million on blended phosphate at approximately $2.5 million per year. The $388 million contract signed in November 2024 dwarfs all previous phosphate spending combined.
The federal Bipartisan Infrastructure Law (2021) allocated $15 billion specifically for lead service line replacement nationwide. Illinois has received approximately $760 million. Chicago has identified $700 million to $1 billion in total available funding — federal, state, and local. Against a need of $8-10 billion, that leaves a gap of $7-9 billion. But $700 million would replace 35,000 pipes at the block-by-block rate — nearly as many as the city has replaced in its entire history. The money is available. The federal deadline is ten years. Other cities have proven it's possible.
The question isn't whether it can be done. It's why it hasn't been.
| Metric | Newark, NJ | Chicago, IL |
|---|---|---|
| Lead service lines | 18,000 | 400,000 |
| Total cost | $120 million | Est. $8-14 billion |
| Cost per line | $6,700 | $35,000 |
| Cost ratio | 1× | 5.2× |
| Time to complete | 3 years | 80 years (current pace) |
| Approach | Block-by-block, free to residents | One-off replacements |
| Lead pipes remaining | 0 | ~386,000 |
Sources: City of Newark, Chicago Dept of Water Management, Grist (June 2025).
At $129 million per year for orthophosphate — and assuming a 5% annual price escalation, consistent with post-pandemic commodity trends of 5-7% — the cumulative cost of the band-aid overtakes the cure faster than you'd think. (Even at a conservative 3%, the crossover still happens within 30 years. At 5%, it's closer to 25.)
Replacing all 400,000 lines at a realistic block-by-block cost of $20,000 per line would cost approximately $8 billion. That's a lot of money. But Chicago is currently on pace to spend that much on phosphate alone within 25 years — while still having 300,000+ lead pipes in the ground.
Even under an aggressive replacement timeline, the city would need corrosion control for the pipes not yet replaced. But does that mean $129 million a year for orthophosphate — or would the blended formula that kept Chicago in compliance for two decades have worked as a bridge? The IEPA's directive to switch implicitly assumes the pipes are permanent. If the plan were to remove them in ten years, the most expensive corrosion control on the market starts to look less like prudent science and more like an admission that nobody expects the pipes to come out.
The per-capita numbers might sound manageable: roughly $4 per person per month for city residents, or $2 across the full 5.3 million people the system serves. Until you realize it's $2 per month forever, escalating every year, to treat a problem that could be solved permanently. In ten years at 5% escalation, that $2 becomes $3.25. In twenty years, $5.30. The tab never stops growing.
And the money goes to completely different places. The annual phosphate bill flows to a single chemical company in Peru, Illinois — population 9,600. It buys a product, not an outcome.
A pipe replacement program would create thousands of local jobs — plumbers, pipefitters, excavators, pavers, inspectors, project managers. Blue-collar work, in Chicago neighborhoods, for a decade or more. Every dollar circulates through the local economy. The work can't be offshored or automated. It's shovels in the ground, block by block.
One option sends money out of the city to buy a chemical. The other invests in Chicago's own workforce and permanently solves the problem. The pipes don't come back. The jobs build skills. The children stop being exposed.
Everyone knows Flint. In 2014, the city switched its water source without adding corrosion control. The protective scale inside Flint's lead pipes dissolved. Lead levels spiked to 13,200 ppb in some homes — 880 times the EPA action level. The crisis cost over $1.5 billion and resulted in criminal charges.
What most people don't realize: pre-crisis Flint tested at approximately 6 ppb — actually better than Chicago's typical 8-10 ppb.
The difference is scale. Flint had about 10,000 lead service lines. Chicago has forty times as many. Chicago has never had a Flint-style acute crisis because it has never stopped adding corrosion control chemicals. But it has a chronic crisis: hundreds of thousands of lead pipes delivering water to millions of people, managed by a chemical treatment that now costs $129 million a year, with no realistic plan to remove the pipes within a generation.
Flint was a sudden disaster. Chicago is a slow-motion one.
After everything you've just read, you might conclude that Chicago simply can't do hard things. You'd be wrong.
In 1867, Chicago completed the most ambitious water infrastructure project in American history. Engineers tunneled two miles under Lake Michigan to reach clean water beyond the pollution of the shoreline. Crews dug from both ends simultaneously — by candlelight, with pickaxes — through clay and rock beneath a Great Lake. When the two shafts met deep under the water, they were seven inches off alignment. Five feet in diameter, brick-lined, built without electricity or dynamite. The city threw a parade when it was done. They had earned it.
But that wasn't even Chicago's most audacious infrastructure project. A decade earlier, between 1858 and 1860, the city had literally raised itself out of the mud. Chicago sat on a swamp, and sewage pooled in the streets. So they jacked the entire city up — four to fourteen feet — to build a drainage system underneath. Entire blocks of buildings lifted on thousands of jackscrews, turned by hundreds of men in coordinated teams. The Tremont Hotel, a massive brick structure at the corner of Lake and Dearborn, was raised six feet while guests slept inside. They woke up on a different horizon and went to breakfast.
In 1900, the city did something that engineers around the world called impossible: it reversed the flow of the Chicago River. The man who made it happen — Isham Randolph — had no engineering degree. He'd started as a railroad axeman. Three chief engineers before him had failed — not because they lacked a plan, but because they couldn't get the elected board of the Sanitary District to approve one. Randolph could. He had a gift the others didn't: he could explain the engineering to non-engineers. He deftly guided the elected board members through the science, translating hydrology and soil mechanics into decisions they could understand and defend to voters. The board didn't just rubber-stamp his proposals. They understood them.
Randolph spent fourteen years as chief engineer, and built the largest canal in the world: 28 miles long, blasted through bedrock, redirecting the river away from Lake Michigan and toward the Mississippi watershed. It was the largest earth-moving project in North America before the Panama Canal. When it was done, President Roosevelt called Randolph to consult on that one too.
When the canal opened, St. Louis sued Chicago for sending its sewage downstream. Chicago won.
Today, the Jardine Water Purification Plant on the lakefront processes 1.4 billion gallons of water per day, serving 5.3 million people. It is one of the largest water treatment facilities in the world.
These were not projects of the left or the right. They were feats of engineering, science, and the refusal to accept that hard problems can't be solved. They were built by people who understood what they were building — and elected officials who understood what they were funding.
When the Illinois EPA mandated a switch that would cost Chicago fifty times more per year, nobody in city government asked to see the analysis. The directive arrived, the contract was signed, and $129 million a year began flowing out of the city. The solution isn't less regulation — it's regulation that shows its work. And a citizenry that knows enough to demand it.
Chicago wasn't built by people who deferred to experts and hoped for the best. The Illinois & Michigan Canal was designed and built by schoolteachers, farmers, and self-taught surveyors. Randolph didn't have a degree — but he made sure the people voting on his proposals understood the science behind them. The Sanitary District board approved the largest canal in the world not on faith, but on understanding. That's the difference between governance and rubber-stamping.
That's the tradition this city comes from. Rooted in Hamilton's 1791 Report on Manufactures, championed by Lincoln: public investment, scientific literacy, and the conviction that ordinary citizens can understand hard problems well enough to solve them. Not a tradition of leaving it to the professionals. A tradition of becoming the professionals.
Chicago mandated lead pipes for ninety years. It had thirty years to replace them and replaced 3.5%. Three mayors promised action; none delivered at scale. Meanwhile, the city wrote a $388 million check for chemicals without questioning whether it was necessary — because nobody in the room understood the science well enough to ask.
This isn't a partisan issue. Replacing lead pipes creates jobs. Federal funding is available. The science is settled. What's missing isn't expertise — it's the civic will to learn enough to demand it.
The pipes are still in the ground. But so is the spirit that built this city. It's time to dig.
Sources:
Check if your home has a lead service line at chicagoleadpipe.com. If it does, share your result — with your neighbors, your alderman, and on social media. The more people who know they have lead pipes, the harder it becomes for the city to pretend the problem is manageable.
If you have a lead pipe, request a free water test kit from the city and filter your water — especially for cooking and for children.
File a FOIA request with the Chicago Department of Water Management for the Illinois EPA directive requiring the switch to orthophosphate, the Carus Corp bid documents, and the city's lead service line replacement timeline. Submit requests through the city's FOIA portal.
Your FOIA request should specifically ask for: (1) the IEPA directive or correspondence requiring Chicago to switch from blended phosphate to 100% orthophosphate, (2) all bid documents, evaluations, and sole-source justifications for the $388 million Carus contract (November 2024), and (3) the city's 10-year lead service line replacement plan submitted under the Lead and Copper Rule Improvements. Address it to the Department of Water Management, FOIA Officer, City Hall, 121 N. LaSalle Street, Chicago, IL 60602.
Contact your alderman and ask what the plan is for replacing lead pipes in your ward — and why it's taking eighty years.
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