I have a home with hardiplank siding. Hired a guy to pressure wash the house and he used bleach and changed it green. I was wondering what I the proper way to repaint the house. Does it need to be recaulked and sealed again or can it be just primed and repainted?

Get Oxyalic Acid and apply with a garden sprayer. Just let it sit. Blowes and Home Cheapo have it unless you can get it through a chemical outlet where it is cheaper. I don't know how many square feet you are dealing with. If he turned it green he probably blew the caulk out also. Better check it. Bleach should only stay on about 5 minutes to do the job and sprayed on from the bottom up to prevent streaking. If you are going to paint it, it should neutralize in a few days and then you can just paint it. If it had paint on it prior to being pressure washed did he use Sodium Hydroxide to remove it? It may be really "fuzzy" from that and you may need to sand it or at least defuzz it with a floor buffer type pad on a drill. Other wise, the finish you put on it will not be the best result.