Charles County, Maryland

Charles is adjacent to Calvert and St. Mary's — largely unsewered outside Waldorf and La Plata sewer cores. Same MDE On-Site Wastewater Professionals / OSDS Registered Individuals list (Updated September 2, 2026) prints registration numbers with streets — those numbers are quoted. Charles County Health Department installation permits require an MDE wastewater-provider number and point applicants to the MDE list; the perc-page link for septic contractors who dig test holes opens a stub without a name table, and Percolation Testing in Charles County (1/2026) does not print a contractor roster — county installer/scavenger numbers are not invented. No official 2024–2026 county tank total was opened this pass; do not invent tank counts. PO Box-only, mixed street/PO Box, St. Mary's streets (29420 Charlotte Hall Road), Calvert and St. Mary's firms already listed, municipal Indian Head rows, and non-septic home-builder/engineer/portable-toilet rows are omitted.

15 listings · board: MDE / MD State Board of On-Site Wastewater Professionals (OSDS Registered Individuals); Charles County Health Department (no public installer/scavenger street roster)

Listings

How we verify