Chicago, Illinois
| Contaminant | Detected | EPA limit | EWG guideline | Status |
|---|---|---|---|---|
| Lead | 3.6 ppb | 15 ppb | 0.5 ppb | 7× EWG |
| Chromium-6 (Hexavalent Chromium) | 0.26 ppb | — | 0.02 ppb | 13× EWG |
| Total Trihalomethanes (TTHMs) | 28.4 ppb | 80 ppb | 0.8 ppb | 35× EWG |
| Haloacetic Acids (HAA5) | 17.5 ppb | 60 ppb | 0.1 ppb | 175× EWG |
| Chloramine | 2.8 mg/L | 4 mg/L | — | — |
| PFAS (PFOA + PFOS) | 2.8 ppt | 4 ppt | 0.004 ppt | 700× EWG |
Context
Chicago has the largest lead service line infrastructure of any US city — an estimated 400,000+ lead service lines connecting water mains to homes. The city has begun a replacement program, but at current pace it will take decades to complete.
Unlike Flint, Chicago's water chemistry is managed to reduce lead corrosion through phosphate treatment. However, any disturbance to lead service lines (construction, water main breaks, even temperature changes) can cause lead spikes at the tap.
A 2018 Chicago Tribune investigation found lead in tap water at levels exceeding the EPA action level in thousands of homes, particularly after water service line work.
Chicago does not bill homeowners for water based on usage (flat-rate billing), which means there is less financial incentive for water conservation and less public attention to water quality issues.
Common questions
Is Chicago tap water safe to drink?
Chicago tap water meets EPA standards at the treatment plant, but the city's 400,000+ lead service lines mean lead can enter water on its way to your tap. The 90th percentile lead level is 3.6 ppb — below the EPA action level but 7x above the EWG guideline. A certified lead-removal filter (NSF 53) is strongly recommended for all Chicago households.
Does Chicago water have lead?
Chicago has the most lead service lines of any US city — over 400,000 lead pipes connecting water mains to homes. While the city treats water with phosphate to reduce corrosion, lead still leaches into tap water, especially when water sits in pipes overnight or after service line disturbances. Test your water and use a certified lead-removal filter.
Is Chicago replacing lead service lines?
Yes, but slowly. Chicago's lead service line replacement program began in earnest after federal pressure, but with 400,000+ lines to replace and limited annual funding, full replacement will take decades. In the meantime, the city offers free water testing kits and filter pitcher programs for qualifying residents.
What water filter is best for Chicago tap water?
For Chicago, the top priority is lead removal. An NSF 53-certified carbon block filter (like the Aquasana Claryum or Clearly Filtered pitcher) handles lead plus chloramine and disinfection byproducts. For the most comprehensive protection, an under-sink reverse osmosis system removes lead, PFAS, chromium-6, and all other detected contaminants.
Chicago's water quality story is dominated by lead. With 400,000+ lead service lines still in the ground, it's the most lead-exposed major city in America.
Lake Michigan via two water intake cribs located 2 miles offshore, drawing from one of the largest freshwater lakes in the world
This data reflects system-wide testing. Your home's plumbing may add or reduce contaminants.
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