ADU Construction & Sewer Connection
Accessory Dwelling Units (ADUs) are an increasingly popular solution for adding value and space to residential properties in Los Angeles. But building an ADU involves more than just laying a foundation and putting up walls—it requires careful planning and full compliance with city regulations, especially when it comes to sewer connections.
At SoCal Sewer & Water, we specialize in managing the sewer infrastructure required for ADU construction. Our experienced team ensures that your project meets all plumbing codes, slope standards, and permitting requirements—so your ADU is not just up to code, but built for longevity.
Why Sewer Line Compliance Matters for ADUs
Los Angeles mandates strict guidelines for ADU sewer systems to ensure safe and sanitary wastewater disposal. Failing to meet these regulations can delay your project, causing costly redesigns, or even result in failed inspections. We help property owners and contractors avoid those pitfalls by handling sewer planning and installation from start to finish.
Key Sewer Specifications for ADUs
Minimum Pipe Diameter
The City of Los Angeles requires a 4-inch minimum sewer line diameter for all individual ADUs. Proper sizing is critical to prevent drainage issues and blockages—especially when multiple plumbing fixtures are involved.
Approved Materials
- City-approved sewer line materials that meet ASTM standards, including:
- ABS (Acrylonitrile Butadiene Styrene): Strong, durable, and reliable.
- PVC (Polyvinyl Chloride): Resistant to corrosion and easy to install.
Slope and Elevation
- Maintaining the correct slope is essential for optimal drainage. We ensure:
- 2% minimum slope (1/4 inch per foot)
- Smooth elevation transitions to prevent backups and preserve flow integrity
Gravity Systems vs. Ejection Systems
Most ADUs are connected to gravity-fed sewer systems, which rely on natural slope to carry wastewater to the main line. When gravity-based connections aren’t feasible—due to elevation or distance—we design and install ejector pumps or low-pressure systems tailored to your site’s needs.
Sewer Connection Options
Every property is different, and so is every ADU sewer solution. Our team assesses the site to determine the best connection method:
Shared Sewer Line
Connect to the main home’s drain line when code allows—ideal for close proximity and cost efficiency.
Separate Sewer Connection:
Required when the main home’s system lacks capacity or the ADU is farther from existing infrastructure.
We consider soil type, property layout, existing infrastructure, and easements to make the best engineering decision for your project.
Permitting and Inspection
Before connecting an ADU to the public sewer, the City of Los Angeles requires:
- Sewer Connection Permit
- Detailed site and plumbing plans
- Sewer Service Charge Application
We manage the permit application and coordinate with the Bureau of Engineering and Department of Building and Safety to ensure everything proceeds smoothly. Once installation is complete, we schedule and facilitate the required inspection for final approval.
Your Partner in ADU Sewer Compliance
With decades of experience in sewer construction and municipal permitting, SoCal Sewer & Water is your trusted partner in ADU development. We deliver:
- Accurate, code-compliant sewer installations
- Guidance through permitting and inspection
- Reliable solutions for challenging properties
- Timely, cost-effective service you can count on
Ready to get started on your ADU project?
Contact SoCal Sewer & Water today for a consultation and let our LA bonded contractors handle the sewer connection—so you can focus on building your future space.