4" Tank Overflow Kit

This flanged 4 inch Tank Overflow Kit is the Overflow Fitting installed on all Poly-Mart Rain Harvesting Tanks. There is a standard rule of thumb when plumbing your rain harvesting system. Rainwater has to be able to exit your tank (when it's at maximum capacity) just as fast as it can enter the tank. If you do not have an adequate sized overflow, your system could back-up and fail during a large rain storm.

The 4 inch Tank Overflow Kit comes with the Overflow Fitting, Hardware, Rubber Gasket, Overflow Screen and Screws! If you can operate a drill and have a 4.5 inch Hole Saw, you can install the 4 inch Tank Overflow Kit. When drilling the hole in the Tank or Container, be sure to let the teeth on the hole saw do the work. Do not apply a bunch of pressure or else the drill will bind up, jump and make your wrists sore!

These 4 inch Tank Overflow Outlets are ideal for a flat surface like the dome flats on all Poly-Mart Tanks. Installing on a round surface or the radius of a round tank could result in a leak.

This flanged 4 inch Tank Overflow Kit uses a "ripple geometry" comb that allows the speed of the overflowing rainwater to be maximized. The combed circumference breaks the water surface and generates a higher outflow which is ideal for high rainfall events.

• Diameter: 4 in