Low profile overbalanced backwater valve

A backwater valve, comprising:

• a hollow valve body having an inlet defined by a vertical surface, an outlet, and a bottom;
• a pivoting valve member pivotally movable about a pivot axis that is positioned below the inlet between a normally open position along the bottom of the valve body and a closed, vertical position sealing the inlet, the pivoting valve member having a peripheral edge comprising a hinge end, a remote end, and opposed sides, the pivot axis being positioned at the hinge end, the pivoting valve member comprising a float;
• and
• a first magnetic element carried by the pivoting valve member and a second magnetic element attached to the hollow valve body adjacent to the inlet, such that, as the pivoting valve member approaches the closed position, the first magnetic element is magnetically attracted toward the second magnetic element to bias the pivoting valve member toward the closed position and to maintain the pivoting valve member in the closed position until sufficient pressure is applied from the inlet to the pivoting valve member to open the valve member.