Not hard to add bacteria to a well if run off water can somehow get into it from the top, or from leaching through the soil. I for one don't care about the bacteria as in 50+ years I know of nobody who has gotten sick from bacteria in a well, or well water that we drink. Our wells are as little as 10 ft deep. Mine is 8 ft deep.I guess I’ve been lucky.
My well system is completely sealed and the water comes from 200 feet in the ground so how is harmful bacteria suppose to get into the water in the first place to start growing.
Educate me on this subject.
As far as getting hot water to the other end of your house. My brother had a circulating pump to do that when he built 20 years ago. you should insulate that line so as not to loose to much heat from it. If you heat with electric it won't make any difference except in summer when you don't want the extra heat in the house. You would even notice it If you would insulate that hot line without a pump. My hot water line to my washroom is 45 ft long. It runs in an open crawl space. The wood furnace is sunk in lower so all the heat from the furnace heats up the crawl space first. When the fire is going all day and I take water in the evening it is warm almost right away. In the morning it is cold. I turn the hot on in the sink a minute before I jump in the shower and that fixes it for me. I do know it takes awhile to get to full heat even if it is warm in a minute(probably only30 seconds). I will probably insulate it some day but it doesn't bother me much the way it is.