A bathroom group is considered to consist of 1 water closet, 1 lavatory, and 1 bathtub (with or without shower head) or a shower stall. When determining the hydraulic load on a pipe, no allowance need be made for a load from a domestic clothes washer when discharged into a laundry tray, since the hydraulic load from the laundry tray is sufficient. No hydraulic load is required from a floor drain in a washroom since it is for emergency use only.