I wouldn`t stick my head under the jet of water just in case it interferes with the tape.... I prefer to use an atomiser bottle filled with water and hair brush.. I kind of `lift`the hair up with the brush and spray --just enough to make it damp. Also the water should be very cool/cold. If you want to wash/shampoo your growing hair you can easily do that in the shower --just incline your head so the jet doesn`t come down directly onto the crown...you can shampoo you hair at the sides/back ....there`s no point in drenching your system in the shower just for the sake of it [it`s not dirty].... I`ve done it before when I was wearing all-poly so the water couldn`t get at the bond---lace is different as it`s totally permeable.... a strong jet of water onto the hair could possibly lead to some tangling too... just go a bit gently at the start until you `find your feet`