Permits and Codes for Sewer Lateral Connection to Main in Maryland

A sewer lateral connection to the main line is a crucial part of any property’s plumbing infrastructure. Whether you’re building a new home, upgrading an aging system, or repairing a damaged lateral, it's essential to understand the permitting process and local codes that govern these connections in Maryland.

At Seadmok Water, we specialize in sewer lateral installation, repair, and inspection services. We’ve helped hundreds of homeowners and property developers navigate the complex permitting process across counties like Montgomery, Howard, PG County, and Baltimore City. Here's what you need to know about permits and regulations for sewer lateral connections in Maryland.

🔍 What Is a Sewer Lateral Connection to Main?

A sewer lateral is the underground pipe that connects a private property’s plumbing system to the public sewer main. This lateral line typically runs from a home or building out to the street, where it joins the municipal sewer system.

This connection must be properly installed and maintained to prevent blockages, backups, and groundwater contamination. Because it interfaces with the public system, it's subject to strict local and state regulations.

📋 Do You Need a Permit?

Yes. Any work involving a new sewer lateral connection, repair, or replacement requires a permit in Maryland. Whether you're installing a new connection for a home addition or replacing a broken line, local authorities must approve the project before work begins.

Most common permits include:

Plumbing Permit – Required for installation and repair work

Utility Permit – Often needed when excavation takes place in public right-of-ways

Road Opening Permit – Necessary when crossing sidewalks or streets to access the main line

🏛️ Maryland Codes & Local Requirements

Maryland’s sewer connection requirements are guided by both state plumbing codes and local county ordinances. While the general process is similar across the state, there are specific differences depending on the county or municipality.

Key considerations include:

Pipe material and size standards

Proper slope and grade of the lateral

Backflow prevention requirements

Connection method to the main line (wye, saddle tap, etc.)

Inspection access points (cleanouts)

Depth and bedding material for pipe installation

Each jurisdiction may have its own approved materials and depth requirements, so it’s important to consult with professionals familiar with local codes.

📍 Examples of Local Codes by County

Montgomery County:

Requires inspection by the Department of Permitting Services (DPS)

Uses WSSC Water plumbing code and standards for residential and commercial properties

Prince George’s County:

Requires permits through WSSC Water for sewer lateral work

Property owners must maintain their own lateral up to the connection point with the main

Howard County:

Overseen by the Department of Public Works

Road openings require specific traffic and restoration plans

Baltimore City:

All sewer lateral connections must follow the Department of Public Works (DPW) guidelines

Excavation in public space requires coordination with the Department of Transportation

👷 Who’s Responsible for the Sewer Lateral?

In most Maryland jurisdictions, property owners are responsible for the entire lateral—from their home all the way to the point where it connects to the main line under the street. If there's a blockage, break, or root intrusion, it’s the homeowner’s job to fix it — even if it’s in the public right-of-way.