Drip tube needed replacing in 4 year old 50 gal. tank so we did that but it did not fix the problem. With a full tank 1 person could have about a 7 minute shower as hot as you want it but then you have to start turning off the cold to make the shower go 15 minutes. Next we replaced the tank with another 50 gal but we still have about the same amount of shower time. We do have the biggest shower head on the market now without the water-saver installed in it but it used to be just the regular shower-head and we still had the same problem. Where is the problem? I was told we should get 8 or 9 showers out of 1 tankful is that right or am I way off?

Gas or electric? Who installed new water heater? What kind of pipe.

Gas heater, neighbor, copper as well as plastic.

What temp do you have it set at and what does the label say about recovery rate? Since this happened with both the old and the new heater I am scratching my head at the moment. Some will think this crazy but another bad dip tube would certainly do it. Many folks think they know how to put in a water heater and about 1/3 of them sweat a pipe too close to the dip tube and cause it to melt off.

Bob,
That was why I ask who installed it.

Did you observe the neighbor install? Did he put the threaded fitting on the water heater and then solder the pipe to it. Or did he solder the threaded fitting to the pipe and then thread the fitting and pipe to the water heater?