Beach · Whatcom County · WA
Is Semiahmoo County Park safe to swim?
No advisory or algae bloom reported for this water today.
Updated July 19, 2026 · Washington beach program (EPA BEACON)
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What's in the water at Semiahmoo County Park right now
As of July 19, 2026, Semiahmoo County Park in Whatcom County, Washington is clear to swim. Blue-green algae are not currently monitored at this water. No fecal-bacteria advisory is posted (state beach program). Rainfall over the past week totaled 0.1 in, which can wash bacteria and nutrients into the water.
Blue-green algae at Semiahmoo County Park
Semiahmoo County Park is a lake in Whatcom County, Washington. Blue-green algae are not currently monitored at this water.
Blue-green algae (cyanobacteria) blooms are most common from midsummer into early fall, when the water is warm, calm, and rich in nutrients from runoff. They can produce toxins that make people sick and can be rapidly fatal to dogs, so skip water that looks green, scummy, or like spilled paint, and keep children and pets out of it.
Frequently asked: swimming in Semiahmoo County Park
- Is it safe to swim in Semiahmoo County Park right now?
- Semiahmoo County Park is clear to swim today. Blue-green algae are not currently monitored at this water. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.
- Does Semiahmoo County Park have blue-green algae (cyanobacteria)?
- Blue-green algae are not currently monitored at Semiahmoo County Park. Watch for green, blue-green, or paint-like scum and avoid the water if you see it.
- Can dogs swim in Semiahmoo County Park?
- No bloom is detected at Semiahmoo County Park today, but dogs are much more vulnerable to blue-green algae than people, and blooms can form within hours. Always keep dogs away from water that looks green, scummy, or discolored, and rinse them off after swimming.
- How many Washington lakes and beaches have swim advisories today?
- Today, 18 Washington waters are under a swim advisory and 9 more warrant caution, out of 1348 monitored waters SwimZone tracks in the state.
- How is Semiahmoo County Park's water quality measured?
- SwimZone builds this read from EPA CyAN satellite imagery for blue-green algae, official beach and fecal-bacteria advisories where a program monitors Semiahmoo County Park, and a recent-rainfall overlay, all refreshed daily. It was last updated July 19, 2026.