DEP algal bloom advisory: updates and information

Current Advisory

10-31-2019 The Lake Hopatcong advisory has been lifted in the Prospect Point and Wood Port Bay area in the northeastern portion of the lake (see advisory status map below). Results from the 10/24 sampling are included in the full report.

Additional sampling was conducted outside of the Prospect Point and Wood Port Bay areas due to observations of localized suspected HABs. Results for 3 locations showed cell counts greater than the health advisory guidance level. As such, localized advisories continue to be recommended for the shoreline at Byram Cove, and now for Pine Tree Point and north of Bertrand Island.

If suspected HABs are observed, please “Avoid It and Report It” to DEP either by calling the DEP Hotline (1-877-WARNDEP (927-6337)) or via the Warn DEP mobile app.

All previous results (6/10/19 – 10/10/19) for Lake Hopatcong sampling stations are available here.

The DEP is taking twice-weekly water samples of the lake and, along with the U.S. Geological Survey, has deployed real-time monitoring buoys to help assess when the lake is safe again for all recreation.

Testing results

For DEP testing results CLICK HERE.
Results will be updated each Wednesday and Friday (after Tuesday/Thursday testing and Wednesday aerial checks).

Real-time monitoring data

For DEP real-time monitoring data for Lake Hopatcong CLICK HERE. For USGS real-time data CLICK HERE.

Health concerns

On Friday, June 28, the Department of Health sent a LINCS (health alert) message to healthcare providers, hospital infection preventionists, and local health departments informing physicians to be aware and consider Harmful Algal Bloom (HAB) related illness in patients reporting swimming in or having contact with Lake Hopatcong. In addition, the New Jersey Communicable Disease Service (CDS) recently launched a waterborne illness web page where information related to HAB illness is provided. You can find the website here:

The Department of Health instructs residents to contact their healthcare provider if they believe they are experiencing symptoms from the HAB.

Algal bloom FAQ

For answers to the questions, we have been most frequently asked, CLICK HERE.

Summary of 7/22/2019 Special Lake Hopatcong Commission Meeting

Lake Hopatcong Commission holds a special meeting about HAB

Summary of 7/8/2019 Lake Hopatcong Commission Meeting

Packed house at LHC meeting to discuss harmful algal bloom

** UDATE 7-3-2019 **

Harmful algal bloom advisory for Lake Hopatcong remains in effect

** UDATE 7-2-2019 **

State Update: Advisory remains in effect, but conditions “somewhat improved”

** ALERT 6-27-2019 **

DEP advises public to avoid contact with Lake Hopatcong water due to harmful algal bloom

“Recreational exposure can occur while swimming, wading and during watersport activities such as jet skiing, kayaking, wind-surfing and paddle-boarding. The DEP is advising the public to avoid these activities and all contact with water from Lake Hopatcong until further notice. People also should not eat fish caught in the lake or allow pets to come in contact with lake water or drink the water.”


For more HAB-related resources, click HERE.


Categories: News, Other, Water Quality, water safety