I have a 50 gallon water heater. The hot water pressure is low through out the hous.

Do you have heat trap nipples on your water heater? When is last time you flush water heater?

Harold could be on the right track. Another thing to consider, how long since you flushed the heater with full wayter pressure through the drain spigot?

Plugged dielectic unions or heat trap nipples is most likely the cause. This is a common occurrence. Please let us know if you need more info. Also, as both experts above mentioned, flushing tank periodically is great preventative maintenance. Lee.

If you don't know how to flush the water heater come back and some one will tell you how to do it, Thanks.

John

Let me tell you now Joeabel, But check to see if you have heat trap nipples coming out of the inlet and outlet of the tank.
For long life and fewer troubles you should keep your heater clear of mineral build-up by FLUSHING NOT DRAINING on a regular schedule. Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run until the water runs clear. You will see a spurt of red,(rust) followed by white or yellow grains,(lime or calcium carbonate). This shouldn't take more then a few minutes. Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures that are affected . Now pull each aerator and clean the screens. Be sure you put them back together the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it. Hope this helps and thank you for rating my answer, Tom