EXHIBIT 11 PENTAIR, INC. AND SUBSIDIARIES COMPUTATION OF EARNINGS PER COMMON AND COMMON EQUIVALENT SHARE Quarter Ended March 31 1997 1996 INCOME ($ thousands) Net income $19,417 $16,500 Preferred dividend requirements 1,218 1,275 Earnings available to common and common equivalent shares - Primary 18,199 15,225 Preferred dividends assuming conversion of Preferred Stock: Series 1988 228 240 Series 1990 990 1,035 Tax benefit on preferred ESOP dividend eliminated due to conversion into common (372) (350) Tax benefit on ESOP dividend assuming con- version to common, at common dividend rate 194 169 Earnings available for common and common equivalent shares - Diluted $19,239 $16,319 SHARES (thousands) Weighted average number of shares outstanding during the period 37,843 37,256 Shares issuable on exercise of stock options less shares repurchaseable from proceeds 404 472 Common and Common Equivalent Shares - Primary 38,247 37,728 Shares issuable on conversion of: $7.50 Callable Cumulative Convertible Preferred Stock, Series 1988 912 962 8% Callable Cumulative Voting Convertible Preferred Stock, Series 1990 3,781 3,962 Common and Common Equivalent Shares - Diluted 42,940 42,652 Earnings per Share: Primary $0.48 $0.40 Diluted $0.45 $0.38