Official sources checked August 31, 2026

Montgomery County, Maryland septic permits and requirements

Maryland state and local framework

Maryland Department of the Environment states that its Onsite Systems Division provides technical direction to County Health Departments and Local Approving Authorities for delegated onsite sewage disposal programs. MDE also states that small onsite systems below 5,000 gallons per day are generally permitted by local health departments, while larger systems can require state groundwater-discharge review.

On-site wastewater professionals have state credential requirements

Maryland law established statewide credential requirements for people providing onsite wastewater services, including design, installation, operation and maintenance, pumping, repair, and property-transfer inspection. MDE states that local approving authorities verify applicable registration or licensing status when issuing septic construction permits, and local requirements may also apply.

DPS is the delegated local septic permitting authority

Montgomery County states that its Department of Permitting Services, acting on behalf of the Maryland Department of the Environment, is responsible for testing for and permitting wells and septic systems in the county. This differs from many Maryland jurisdictions where a local health department performs the same delegated function.

New systems and certain building additions require a septic permit

A county septic permit is required to install a system for a new home and to upgrade or replace an existing system to accommodate a building addition. For building-permit applications received on or after July 1, 2024, when an addition or alteration requires septic components to be upgraded or relocated, the septic work and permit conditions must be completed before the related building permit can be approved and issued.

Permit application, plan review, and fees are handled through DPS

Montgomery County allows online septic applications and requires a nonrefundable filing fee at application. For electronic applications, required plans must be uploaded within five business days or the application can be voided. The county directs applicants to its current DPS fee regulation rather than publishing a fixed fee in the septic process page, so SepticScope does not hard-code a dollar amount here.

Permits expire after twelve months unless extended once

Montgomery County states that septic system permits are valid for 12 months from issuance and may receive one six-month extension. After expiration, a new application and fee are required.

At least two installation inspections are required

Once a new septic installation begins, Montgomery County requires a minimum of two inspections. Final system approval is issued only after the system is complete, required inspections pass, and all permit conditions are satisfied. The county advises owners to retain the approved permit and as-built drawing.

Failing-system replacements use a separate repair process

Replacement of a failing septic system requires a septic repair permit. Montgomery County states that repair permits are expedited based on available information, and the installer must request inspection before installation begins.

County management program provides maintenance resources

Montgomery County Department of Environmental Protection operates an onsite well and septic systems management program that provides operation and maintenance guidance and a voluntary maintenance-reminder service. These resources support long-term system care but do not replace DPS permit or inspection requirements.

Official sources

• Maryland Department of the Environment — Onsite Systems Division
• Maryland State Board of On-Site Wastewater Professionals
• Montgomery County DPS — Septic Permit Process
• Montgomery County DPS — Septic System Repair Permit Process
• Montgomery County DEP — Onsite System Testing and Permitting
• Montgomery County DEP — Onsite Well and Septic Systems Management Program

SepticScope summarizes public-agency information for planning purposes. The permitting agency's current instructions control if they differ from this guide.