Where I brew has the same problem, although I wouldn't describe it as bad or as strong as you are. How do you draw your water; straight from the tap or a garden hose? If it is a garden hose like me, then just buy an RV water filter that connects to a garden hose. It greatly reduced the sulpher to barely negligible. Also, I would think the 1 hour boil precipitates out the remaining sulfer. I don't have any science to back my theory, but what I do know is that in drinking the final product you would never know the water had sulpher smell/taste to it. Sent a few beers for comps and not one returned with a comment of sulpher smell/taste.