INDIRECT CONNECTION:
- Procedure: The ADU’s sewer line connects to the main house’s existing sewer line.
- Costs/Fees: Lower than direct connections, as less construction is needed and capacity fees may be avoided.
- Time: Shorter, with simpler installation.
- Process: Easier and faster approval, though local rules may vary.
DIRECT CONNECTION:
- Procedures Involved
- Sewer Lateral Installation: The direct connection involves installing a new sewer lateral, which is an underground pipe connecting the ADU’s plumbing directly to the main public sewer line. This work is typically more complex than an indirect connection because it may require trenching through the property and, in some cases, the public right-of-way.
- Permitting and Inspections: You’ll need permits from your local city or county, which cover the excavation, installation, and connection to the public sewer. Inspections are conducted at various stages to ensure compliance with building codes and regulations.
- Civil Design Work: In some cases, particularly when the sewer lateral crosses public property or must navigate around existing infrastructure, civil engineering design work is required. This ensures that the new connection does not interfere with public utilities and complies with municipal standards.
- Installation of Cleanouts: Cleanouts are required at the point where the new sewer line connects to the main line. These allow for easy access in case of blockages or maintenance needs.
- Sewage Ejection Pump: If the ADU is situated below the level of the main sewer line, a sewage ejection pump might be necessary to move wastewater uphill to the main line. This system includes a basin and venting, adding complexity and cost to the project.
- Costs Involved
- Sewer Lateral Installation: The cost to install or upgrade a sewer lateral can range from $20,000 to $30,000. This includes excavation, pipe installation, and potential civil design work.
- Permits and Fees: Permitting fees vary by location but can range from $5,000 to $15,000 depending on the scope of work and local regulations. These fees cover the administrative costs of processing permits and conducting inspections.
- Sewage Ejection Pump: If required, the installation of a sewage ejection pump can add an additional $5,000 to $8,000 to your project. This is necessary if your ADU is below the grade of the main sewer line.
- Excavation and Trenching: Costs for excavation and trenching depend on the distance from the ADU to the main sewer line and any obstacles in the way, such as existing utilities or large trees. This can add significant cost, often several thousand dollars more if deep or extensive trenching is required.
- Pipe Material and Size: Typically, a 4-inch diameter PVC or ABS pipe is used for residential sewer lines. The choice between materials depends on local building codes and environmental conditions, with PVC generally being more affordable but ABS being more durable in cold climates.
- Time Involved
- Design and Permitting: The permitting process can take several weeks to months, depending on the complexity of the project and the responsiveness of local authorities.
- Installation: The actual installation, including trenching, pipe laying, and backfilling, can take several days to weeks. If a sewage ejection pump is needed, additional time is required for its installation and integration.
- Important Considerations:
- Slope and Distance: The farther and steeper the slope from your ADU to the main sewer line, the higher the costs due to more complex excavation requirements and potentially the need for a sewage ejection pump.
- Local Regulations: Each city or county has its specific requirements, which can greatly influence both the process and costs involved.
- Overall, a direct connection can be quite costly and complex, but it’s often necessary to comply with local codes and ensure proper sewage management for your ADU. Consulting with local contractors and municipal authorities can help you get precise estimates and a clearer understanding of the process specific to your location