Sources
This site does not perform the work it writes about. What it can do is be exact about the rules, and show you where every rule comes from so you can check it yourself. Every requirement, deadline and frequency stated anywhere on this site traces back to one of these.
310 CMR 15.000: Septic Systems (Title 5)
MassDEP. The regulation itself. Everything on this site about inspections, transfers and system requirements traces back to this text.
New septic system regulations to mitigate nitrogen pollution on Cape Cod
Commonwealth of Massachusetts. The July 2023 amendments that created Nitrogen Sensitive Areas and the Watershed Permit pathway.
2023 Title 5 Regulation Changes
Barnstable County, MASSTC. The county's own homeowner-facing explanation of what changed on Cape Cod.
Title 5 Factsheet
Barnstable County. Plain-language summary of inspection requirements.
Regulations change, and local authorities can be stricter than the state. Where this site says a rule varies by town, check with the office named on the page rather than relying on a summary.