These Massachusetts beaches are closed as of Aug. 1

Before hitting the beach this weekend, check out this list of closed waterfronts.

Massachusetts heads into yet another heatwave this weekend. If you want to cool down at the beach, make sure you visit a safe and open one. These 49 beaches across Massachusetts are closed as of Thursday, Aug. 1 due to bacteria concerns.

The state’s Department of Public Health says bacteria levels tend to rise right after periods of heavy rainfall. Dirty runoff from the streets gathers excrement and other harmful bacteria in the sewers, which in turn can run into nearby bodies of water.

In Worcester, authorities closed Indian Lake pond due to a very large cyanobacteria presence in the water. The Department of Inspectional Services say they normally add a bit of polyaluminum chloride to the water via a dosing station at the mouth of the lake. Usually, this small amount of chemicals reduces the growth of toxic bacteria in the water. However, recent “low flow” of water into the lake reduced the effectiveness of the chemicals. If you or your pet came into contact with the contaminated water, you should immediately wash off in freshwater, authorities said. If your pet ingested the water, take them to the vet immediately.

Swimming in unsafe water can lead to a bevy of health problems. The most frequent and notable effect are gastrointestinal symptoms, like nausea and diarrhea. When ingested, bacteria can also cause flu-like symptoms, skin rashes, and eye-nose-throat problems.

It is unclear when the beaches will reopen. Water testing results take 24 hours, the DPH says, so results typically come out the next day. For now, the department warns beachgoers to be vigilant and check their interactive beach water quality dashboard.

List of beaches closed as of Thursday, Aug. 1

Beaches with an * indicate beaches that were closed for over a week

Amherst

• Puffers Pond*
• Stanley St. swimming hole*

Ashby

• Damon Pond Beach*

Barnstable

• Kennedy Memorial/Veterans Beach

Beverly

• Independence Park

Boston

• Malibu*
• Savin Hill
• Tenean*

Chatham

• Bucks Creek*

Concord

• Walden Pond*

Danvers

• Sandy Beach

Dartmouth

• Moses Smith Creek

Framingham

• Waushakum Beach

Freetown

• Freetown Town Beach

Grafton

• Silver Lake Beach

Great Barrington

• Lake Mansfield

Greenfield

• Greenfield Municipal Bathing Beach*

Harwich

• Sand Pond

Holland

• Collette Drive Beach*

Lynn

• Kings*
• Lynn Shore Beach*

Marblehead

• Grace Oliver

Nahant

• Nahant Beach

Nantucket

• Sesachacha Pond*
• Washing Pond*

Natick

• Cochituate State Park Beach

North Andover

• Stevens Pond – Center*

Oxford

• Carbuncle Pond*

Rutland

• Whitehall Pond Beach*

Salem

• Camp Naumkeag*
• Children’s Island*
• Ocean Avenue
• Osgood

Sherborn

• Farm Pond

Shutesbury

• Lake Wyola*

Swampscott

• Fisherman’s
• Kings*

Swansea

• Leeside

Taunton

• Watsons Pond*

Templeton

• Beamans Pond*

Townsend

• Pearl Hill Pond Beach*

Truro

• Longnook*

West Stockbridge

• Card Pond Beach*

West Tisbury

• Long Cove*
• Seth’s Pond*

Westminster

• Crow Hill Pond Beach*

Winchendon

• Lake Dennison

Worcester

• Lake Quinsigamond-Regatta Point Beach*
• Indian Lake