American Water Announces Exercise of Over-Allotment Option

Company Completes Common Stock Offering
VOORHEES, N.J.--(Business Wire)--
American Water Works Company, Inc. (NYSE:AWK), the largest investor-owned U.S.
water and wastewater utility company, today announced that the underwriters of
the company`s public offering have exercised their over-allotment option and
purchased 3.9 million additional shares of common stock from the selling
stockholder in the offering, a subsidiary of RWE AG.

American Water also announced the completion of the public offering of 29.9
million shares of its common stock, which had been priced at $17.25 per share.
Pursuant to the offering, American Water sold 14.5 million shares of common
stock, and 15.4 million of the shares were sold by RWE, including shares sold
prior to the over-allotment option. RWE now owns approximately 46.6 percent of
American Water`s outstanding shares of common stock.

This press release shall not constitute an offer to sell or the solicitation of
an offer to buy, nor shall there be any sale of these securities in any state or
jurisdiction in which such offer, solicitation or sale would be unlawful prior
to registration or qualification under the securities laws of any such state or
jurisdiction.

An effective registration statement relating to these securities is on file with
the U.S. Securities and Exchange Commission. A copy of the final prospectus and
prospectus supplement may be obtained when they are available by contacting any
of the following:

• Merrill Lynch & Co., Attention: Prospectus Department, 4 World Financial
Center, New York, NY 10080, telephone +1 212 449 1000.

• Citi, Brooklyn Army Terminal, 140 58th Street, 8th Floor, Brooklyn, NY 11220,
telephone +1 718 765 6732.

• Goldman, Sachs & Co., Attention: Prospectus Department, 85 Broad Street, New
York, NY 10004, facsimile +1 212 902 9316, e-mail prospectus-ny@ny.email.gs.com.

You may also obtain the final prospectus and prospectus supplement when they are
available on the Securities and Exchange Commission's website at
http://www.sec.gov.

About American Water

Founded in 1886, American Water is the largest investor-owned U.S. water and
wastewater utility company. With headquarters in Voorhees, N.J., the company
employs more than 7,000 dedicated professionals who provide drinking water,
wastewater and other related services to approximately 15 million people in 32
states and Ontario, Canada.

American Water
Edward Vallejo
Vice President, Investor Relations
856-566-4005
edward.vallejo@amwater.com
or
Maureen Duffy
Director, Communications
856-309-4546
maureen.duffy@amwater.com

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