[header] How to change a dip tube [title] Check when your water heater was manufactured. [step] 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. 
[substeps] Look on your water heater for the serial number. This is probably on the back of your tank.