Legal Question in Real Estate Law in Massachusetts

You would need to prove that they were in fact negligent and not just that the system failed. Septic systems have a life expectancy depending on the material they are constructed from and the way in which they are used (ie. what gets flushed into them). A trustee who breaches his fiduciary duty to "maintain, repair, and replace" common areas (such as septic) is liable for the cost of returning the unit owners' association to the position that it would have been in had such steps been undertaken. In circumstances such as those present here, where the cost of repair and replacement, if undertaken, would have been assessed against the unit owners association as "common expenses," the liability of a trustee (if any) would be limited to additional costs incurred as a result of the delayed undertaking of those tasks.

So... maybe, provided the cost of joining the municipal sewer is more than what it would have cost to maintain, repair and replace the septic system (to the extent replacement is limited by Provincetown's Board of Health septic/sewer regulations.