Friends of Lake Twelve
Lake Twelve is a small freshwater lake in the heart of Black Diamond, Washington — a cherished natural gem in southeast King County. Surrounded by a close-knit residential community, it has served for generations as a gathering place for fishing, wildlife watching, and quiet enjoyment of the outdoors.
A public boat ramp makes Lake Twelve accessible to all Black Diamond residents — not just shoreline property owners — and the lake supports an active recreational fishery enjoyed by families and anglers from across King County District 9.
Our Volunteer Monitors: Jill & Ken Eide
Community members Jill and Ken Eide have served as Lake Twelve's official volunteer monitors for King County's Lake Stewardship Program since at least 2017. Their dedicated twice-monthly sampling provides the scientific foundation for understanding — and restoring — the lake's health.
📊 View all monitoring data at the King County Lake Twelve monitoring portal.
Explore the Site
💧 Water Quality
Rising phosphorus, invasive plants, and noxious weeds — what the data shows and why it matters.
🦦 Wildlife
River otters, Great Blue Herons, and the rich ecosystem that depends on a healthy lake.
🌿 Restoration
Our $88,550 WaterWorks grant project — the plan, the partners, and the timeline.
🚣 Recreation
Fishing, boating, and public access at Lake Twelve's community boat ramp.