2 inch wide precast trench drain. $ 684.80 – $ 861.04. 4 inch wide precast trench drain. $ 922.20 – $ 1,991.12. 6 inch wide precast trench drain. $ 1,150.64 – $ 1,800.24. 8 inch wide precast trench drain. $ 1,149.76 – $ 1,799.36. 10 inch wide precast trench drain.