Xylem (XYL) 10-Q/A 2012 Q3 Quarterly report (amended)

EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report on Form 10-Q of Xylem Inc. (the “Company”) for the period ended September 30, 2012 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Gretchen W. McClain, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. 1350, as adopted pursuant to 906 of the Sarbanes-Oxley Act of 2002, to my knowledge, that:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(2) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

/s/ Gretchen W. McClain

Gretchen W. McClain

President and Chief Executive Officer

November 5, 2012

A signed original of this written statement required by Section 906 has been provided to Xylem Inc. and will be retained by Xylem Inc. and furnished to the Securities and Exchange Commission or its staff upon request.