The southwest side of the Sleepers drains into Slide Brook and Cascade Brook, both of which drain into Avalanche Brook, thence into the Mad River, Pemigewasset River, Merrimack River, and into the Gulf of Maine at Newburyport, Massachusetts. The northeast side of the Sleepers drains into Sabbaday Brook and Downes Brook, which both drain into the Swift River, thence into the Saco River, and into the Gulf of Maine at Saco, Maine. The south end of East Sleeper drains into the Whiteface River, thence into the Cold River, Bearcamp River, Ossipee River, and the Saco River.