Our well is separate from our house. How close does it need to be to the house?

It should be in the house or at the outside wall of the house depending on basement or slab foundation. It should be after the pressure tank and filter if they are closer to or at the house. Also, well water should use the SB-ELITE as the well water is usually too hard for the SB-75's capacity. You can either search SB-ELITE, or copy and paste the below link. Using the right unit for your water is critical to effectively condition the water! https://www.homedepot.com/p/ScaleBlaster-20-gpg-Deluxe-Model-Electronic-Water-Conditioner-Weather-Proof-SB-Elite/301275934