What determines how much hot water pressure you get? I have very little hot water pressure in the kitchen and shower, but decent water pressure in the laundry tub in the basement. What are some possible problems.

"what are some possible problems?"
Mineral build up in a water heater that's not being flushed can get in the pipes and clog up the inlet ports in the cartridges. The solutio0n is to shut the water off and open up the faucets. Check and clean the inlet ports in the cartridge and then, while the valves's still open turn the hot water on for a moment to flush the hot water supplies out. If you don't flush your heater on a regular maintenance schedule let me show you how. For long life and fewer troubles you should keep your heater clear of mineral build-up by flushing 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 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. Now pull each aerator and clean the screens. Be sure you put them back togather 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, Tom