It is something of a truism that West Marin is ruled by septic. Homeowners who set out to add a bedroom, build a deck or remodel a kitchen often find their county-issued permit comes with an unwelcome companion: a septic review. The inspection can expose outdated or undersized systems and trigger repairs or replacements that can run upwards of $100,000.
Now, Marin County is preparing to overhaul the regulations that govern its roughly 8,000…