.W.
water heater - here is a picture of standard gas and electric water heaters.
Please note; mobil home water heaters are diffrent and double the cost. over head water heaters need vacume breakers, many areas require safe pans with drains and make sure the water does not exceed the hot water limit, get witness verification (measured from the closest fixture)
wax ring - come with a horn or not. Often used for connecting the toilet to the toilet collar/flange.
wye - another fitting, comes in all sizes, makes, and forms, this is a glue, pvc "Y"
