One of the house repairs I recently did before Chinese New Year 2016 was to fix a problem in my bathroom whereby the water flow from the tank to the toilet bowl was very slow.
I found that the metal hose connecting the tank to the toilet bowl was brittle, when I put pressure on it a bit, I could see some leakage.
Upon removing the metal hose and replacing it with a new hose, I also found the pipe was clogged by filth and dirt and proceed to clean it using a screw driver.
After doing all these the water flow improved tremendously.