Premise: How to change a dip tube<br>Check when your water heater was manufactured. Nearly all gas and electric water heaters manufactured between 1993 and 1997 were installed with defective dip tubes. The dip tubes were made of a material that quickly degraded and disintegrated, causing dip tube failure.
Hypothesis: Only dip tubes made from 1993 to 1997 are defective any any tubes made in previous or later years are without fault.