Largest Water Utilities Companies by Market Cap

American Water Works, founded in 1886, is the largest publicly traded water utility in the United States, providing drinking water and wastewater services to over 14 million people across 14 states. As a regulated monopoly, it operates without competition in the regions it serves — a structure common across the water utilities sector.

Water utilities account for just 2.6% of the broader Utilities sector under the GICS classification, but they cover essential services: water collection, purification, distribution, sewage collection, wastewater treatment, and materials recovery. The industry does not include bottled water manufacturers, which belong to the food sector.

The largest water utilities companies are listed across multiple countries:

• United States: American Water Works (AWK), Essential Utilities (WTRG), American States Water (AWR), California Water Service Group (CWT)
• United Kingdom: Severn Trent — serving around 8 million customers in the Midlands — and United Utilities, the UK’s largest listed water and wastewater company, covering over 3 million homes in North West England
• Brazil: SABESP and SANEPAR, both regulated water utilities listed on Brazilian exchanges
• China & Hong Kong: Chongqing Water Group, Beijing Enterprises Water Group, and China Water Affairs Group
• Middle East: Alkhorayef Water & Power Technologies in Saudi Arabia, where desalination is a growing focus

Beyond pure water utilities, the industry also includes infrastructure providers that build and maintain pipes, pumps, and desalination plants, as well as technology developers focused on filtration, leak detection, and water recycling. Several indices track this space, including the S&P Global Water Index (approximately 50 securities) and the ISE Clean Edge Water Index (top 36 water-related companies). Popular ETFs such as Invesco Water Resources ETF (PHO), Invesco S&P Global Water ETF (CGW), and First Trust Water ETF (FIW) provide broad exposure to the sector.

York Water Company, founded in 1816, stands out as the oldest investor-owned water utility in the United States, serving three counties in south-central Pennsylvania. For a broader look at the largest utility companies across all sub-sectors, see our dedicated page.

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The following table contains a list of the largest water utility companies by market capitalization, covering regulated utilities and related water service providers traded on global exchanges. The list includes only publicly traded companies, and the presented data (price, market cap) are regularly updated to reflect the current market situation.