Translate
Black Diamond sewer upgrade
The Black Diamond Sewer Upgrade Project will increase capacity for 6 miles of regional sewer pipe in Black Diamond. The project will help us treat more wastewater to meet the needs of the growing Black Diamond community.
Project description
Upgrading the sewer pipe to meet Black Diamond's growth
Black Diamond is one of the fastest-growing communities in the Puget Sound region. In 1992, in collaboration with King County, the City built a regional sewer line to serve the area’s much smaller population at the time. Today, we need to upgrade the existing sewer line because it’s reaching capacity. Upgrading the sewer line may include a combination of repairing the existing pipe and installing new pipes
The project will look at options to upgrade 6 miles of sewer pipe in Black Diamond. The option we select will:
- Serve the community’s wastewater capacity needs through 2070
- Ensure reliable wastewater service to Black Diamond's homes and businesses
- Foster a healthy and resilient community with reliable wastewater infrastructure
Project update
April 2025
Wetland sampling along the regional sewer pipeline planned for April 10 through April 15
Starting as early as April 10, field crews will collect soil samples to map the boundaries of wetlands along the existing pipeline (see map below). The soil samples will inform design. Private properties will not be surveyed or accessed during this fieldwork.
Crews will use hand shovels to dig a small hole in the ground and record observations of soil, vegetation, and hydrology to identify wetlands. Any confirmed wetlands will be marked by placing pink flags. Crews will fill and restore all work areas. This work is expected to be completed in one day and take approximately 30 minutes at each site. Depending on site conditions, the work may take an extra day and will be completed by April 15. This work may reoccur quarterly.
For more information, view the April 9 bulletin.
Read this email in: Español (Spanish)
Previous project updates
Project location
Understanding site conditions and community needs
Our team is in the early stages of design for the project. During the design phase, the project team will:
- Survey the project area to understand existing conditions in Black Diamond
- Conduct geotechnical surveys to understand underground conditions
- Inform community members about the project and upcoming survey work
- Analyze design alternatives and identify a preferred option to upgrade the sewer
- Complete 30% design for the project
Working with the community
We’ll share details about specific engagement opportunities as the project progresses
We’re committed to engaging with the community during each stage of the project, and we want to make sure everyone has access to information. We welcome you to take part in the project in the following ways:
- Contact us to have a one-on-one conversation by phone, video chat, email, or in person.
- Invite us to a meeting hosted by your group or organization.
- Join our team remotely or in person at future meetings at project milestones. We will post these meetings on our website and email list once they are scheduled.
Interpretation and translation services are available to you at no cost. If you need them, please contact Annie Plumley, aplumley@kingcounty.gov, 206-263-3203
Los servicios de interpretación y traducción están disponibles para usted sin costo alguno. Si los necesita, comuníquese con Annie Plumley, aplumley@kingcounty.gov, 206-263-3203