“Why are sewer/drain lines, ground settling impacts on foundations and sidewalks, and water supply lines not on our reserve study?”

These items are not typically considered reserve expenditures due to the unpredictable nature of the replacement (when will it occur, where will the problem be located, and how much will the repair/replacement cost be) of the component. Your typical reserve component has a predictable replacement cost, a predictable replacement cycle, and will occur on a cyclical basis. Unfortunately, these are all very difficult items to predict if or when failures will occur. However, if there are professionals that we can contact to get their opinion on the conditions and hopefully arrive at an estimated cost, then we could consider including these expenses in the report.