•1,000 ft. of 4-in. tile installed                    $2,300

•Water control box                                  1,100

•Design                                                            100

•Capital/opportunity cost (4%, 20 yrs)    1,460

Total Cost                                             $4,960

            •Amortized over 20 years                         $248/year

            •First year cost/lb. N removed                          45¢/lb. N