A group of Stony Brook scientists made an app that lets you make sure where you’re swimming is sanitary water.

Dr. Chris Gobler, of Stony Brook, says the app shows users what the water quality is like at over 200 beaches across the Island and a total of 500,000 acres of bodies of water.

"It just occurred to us what if you have that all at your fingertips," says Gobler.

The app also shows where you can and can’t shellfish. Baymen in Southampton say it will be very useful.

Dr. Gobler says the app is the first of its kind for Long Island.

The Long Island Beach and Water Quality app can be downloaded here.