I can't speak to island properties, except that some still have outhouses! (Though they may actually be better than "septics", depending...)
Non-existant runoff control
uphill washed my neighbor's entire 1940s-era system into the lake in a July 2000 thunderstorm. Good riddance, as the tank's location was revealed by the storm's runoff and discovered to be only 20' from the lake.
My other neighbor sold out to a spec-builder (in the "used-house" business—no offense to Realtors
®) who installed a new house adjacent—
but right in the middle of the old septic system! Town-approved, both share a new drilled well, and both pump effluent into the existing house's new field. That new field has a continuous, but mostly odorless, trickle around its periphery. Once occupied for the season—and depending on the wind direction—suspicious odors waft my way: the Health Department is happy—what's left for
me to do?
Uphill—where the lack of runoff-control begins, a developer has put in a septic system to service 20 yet-to-be-built homes. It abuts an immense rock ledge, which is unlikely to provide good leaching capacity. The system's several "lollipops" can be easily seen from Winter Harbor, which has a single small outlet to The Broads for dilution. Algae clumps are a problem in Winter Harbor, where only a minority of lakefront homes have grassy lawns.
IMHO, "slap-dash septics" may be the reason that NH wishes to extend its oversight beyond ~200' from the lake, and not leave it up to the respective Town inspectors and Health Departments.
BTW: A distant lake I frequent requests a pumpout "every three years".
I'd like to see a
pumpout requirement upon the sale of every lakefront home—in addition to "an inspection". There's an adequate turnover of lakefront homes to justify this requirement.