1. The problem statement, all variables and given/known data I know what causes water hardness, how it can be resolved (or dissolved - hehe), but I'm not sure why certain parts of pipes would be harder than others. Specifically, why the water on the 1st and 2nd floor of a building would be harder than that on the 3rd and 4th floor. I have to write a ten page paper on these findings, and I'm stumped. Suggestions? Possible causes? 2. Relevant equations 2 HCO3– → CO32– + CO2 3. The attempt at a solution The only thing I can think of is that is may be warmer in the basement making the Ca2+ ions react with bicarbonate forming buildup.The problem is, the water from the same pipes (I assume) travels to the top floor. HELP!!!