The world largest drinking water treatment plants produce over 3 billion litres per day each. They serve mega city populations from Chicago to Sao Paulo to Delhi. This guide ranks the 15 largest by capacity.
The ranking
| Rank | Plant | City | Capacity (m3/day) |
|---|---|---|---|
| 1 | Jardine | Chicago, USA | ~5,700,000 |
| 2 | Guarau | Sao Paulo, Brazil | ~5,000,000 |
| 3 | Wanaka Kayaba | Beijing, China | ~4,000,000 |
| 4 | Bhandup Complex | Mumbai, India | ~3,500,000 |
| 5 | Sonia Vihar | Delhi, India | ~2,700,000 |
| 6 | Wanjiazhai | Shanghai, China | ~2,500,000 |
| 7 | Rio Cotia | Sao Paulo, Brazil | ~2,000,000 |
| 8 | Tampines and others | Singapore | ~1,800,000 combined |
| 9 | Sydney Prospect | Sydney, Australia | ~2,000,000 |
| 10 | Los Angeles Aqueduct WTP | Los Angeles, USA | ~1,700,000 |
| 11 | Chinandega | Nicaragua | ~1,500,000 |
| 12 | Cheongju | South Korea | ~1,300,000 |
| 13 | Kluczbork | Poland | ~1,200,000 |
| 14 | Ashkelon | Israel | ~1,000,000 |
| 15 | Manila East | Philippines | ~1,100,000 |
Jardine: the largest
Jardine Water Purification Plant on Chicago lakefront is the largest drinking water plant globally. Draws from Lake Michigan; produces up to 5.7 million cubic metres per day. Operated by the City of Chicago Department of Water Management. Uses conventional coagulation, sedimentation, filtration, and disinfection.
Guarau: Sao Paulo scale
Guarau near Sao Paulo produces around 5 million m3 per day for one of the largest urban populations in the Americas. Draws from the Cantareira reservoir system. Operated by SABESP.
Asian mega plants
Beijing, Mumbai, Delhi, and Shanghai all operate plants above 2 million m3 per day. Bhandup in Mumbai and Sonia Vihar in Delhi serve mega city populations exceeding 20 million.
US treatment scale
Jardine leads in the US; other large plants operate in New York (Croton, Delaware Aqueduct WTP), Los Angeles, Detroit, and Houston. Some US mega cities use multiple plants for reliability.
Combined top 15 capacity
Technology
All top 15 use conventional coagulation, flocculation, sedimentation, filtration, and disinfection. Advanced treatment (GAC, ozone, membrane) is present at some plants. See our companion article on how a water treatment plant works.
Ongoing upgrades
Each top 15 plant is undergoing upgrades for emerging contaminants (PFAS, pharmaceuticals), climate resilience, and cybersecurity. Total spending on top 15 upgrades likely exceeds USD 10 billion by 2035.
Source water
| Plant | Source |
|---|---|
| Jardine | Lake Michigan |
| Guarau | Cantareira reservoir |
| Sonia Vihar | Yamuna canal |
| Bhandup | Tansa lake |
| Los Angeles | State water project and Colorado River |
Climate impact
Drought, algal blooms, and heat all affect source water. Plants are increasingly designed to handle variable feedwater quality. See treatment plant climate resilience.
Staffing scale
Top 15 plants employ 200 to 800 staff each, plus support functions in laboratories, control rooms, and maintenance. Certified operators handle 24/7 operations.
Reliability
All top 15 have redundant treatment trains and can continue operating with one line down. Backup power, multiple intake locations, and treatment redundancy are standard.
Future rankings
Chinese and Indian plants will grow. New water reuse plants may enter the ranking as reuse scales. Traditional US and European plants will remain but under continuous upgrade.
Frequently asked questions
Which is the largest water plant?
Jardine in Chicago.
How is capacity measured?
Peak design flow. Average operation is 60 to 80 percent typically.
Do these plants serve their whole cities?
Usually most of city demand. Very large cities have multiple plants.
Are they publicly owned?
Most yes. UK plants under regulated private ownership.
Do they treat lake, river, or reservoir water?
Varies. See source water table above.
What is treatment level?
Full conventional plus disinfection. Some have advanced treatment.
Are they resilient to climate change?
Increasingly, through source water diversity and treatment upgrades.
Do plants use ozone?
Some yes as disinfection or oxidation.
What about PFAS?
Growing focus. GAC and other technologies being deployed.
Where can I see plant data?
The UtilityRadar directory lists water treatment plants.
Summary
The world 15 largest drinking water plants combine roughly 36 million cubic metres per day of capacity, serving 180 million people. Jardine in Chicago leads. Asian mega city plants are rising rapidly in the ranking. Ongoing upgrades address emerging contaminants, climate resilience, and infrastructure age.
Next reading
- How a water treatment plant works
- How many water treatment plants globally
- Where does drinking water come from
- Browse the UtilityRadar directory
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