If it is gas, then that is probably the problem. Some plumbing stores have new dip tubes which you insert down the cold water opening on the top of the tank, otherwise a piece of 1/2 copper tube flared do it doesnt drop through will work. This can also be a problem with electric heaters, but the more likely thing is that the lower element is burned out, and the upper thermostat is either not adjustable or set low.: Our Rheem Ruud water heater is only 1.5 years old and is providing only about 2 min. of shower time. This only started happening recently. Someone said it might be my dip tube. If so, how do I fix it? If not, what is wrong??