Deteriorating water distribution systems are a common problem facing many waterutilities. Nationwide, the cost of replacement and rehabilitation is estimated at 23 plus billion dollars.It is virtually impossible to replace all vulnerable pipes at the same. There is a need for methodsthat can help in progressive rehabilitation and replacement subject to budgetary constraints. Ifdelaying is considered a good strategy due to the time value of money, the timing of preventivemaintenance becomes a crucial element for system maintenance and operation. The central underpinning element in the decision process is the deteriorating nature of a pipe in a givensurrounding. In this paper, a mechanistic analysis framework for the replacement of pipes ispresented. The associated software is in the form of a user friendly spreadsheet program. Adescription of the software is also given. Includes 8 references, tables, figures.