To turn on the hose, go to the store and buy the waterproof tape.  If it is not there, you will have to wait for the store to refresh itself.  Once you have the tape, place it on the hose.  Then, drop an adult on the hose and they will start to repair it. Hope this helps!

First, make sure you have fixed the hose at the back of the house by buying the tape and dropping an adult on it.
 
Next, you need to buy the wall compound from the store. If it is not there, you will probably have to wait until the store refreshes its items a few times.  Once you have it, place it by the green bucket near the sandbox at the front of the house.  Drop an adult on the bucket and they will pick it up and take it to the workshop wall.
 
Drop the adult on the bucket again and they will start repairing the wall.  It will take a few times for them to finish, but keep dropping them on the bucket and this should work. Hope this helps!