NDS Flo-Well FWAS24WH 50 gal Black Stormwater Dry Well System Kit with 3 Side Panels & Cover. Installed underground, the Flo-Well Dry Well collects, temporarily stores, and slowly releases excess water into the ground. Unlike traditional dry wells which require filling a hole with heavy stone and gravel, the Flo-Well system only needs a small amount of gravel at the base of the tank to prevent scouring. The gravel-free interior provides 250% more detention volume than comparable-sized gravel dry wells. The 50 Gal. Flo-Well Stormwater Dry Well System Kit comes with 3 side panels & 1 cover made of high density polyethylene (HDPE). Hassle-free limited lifetime warranty guarantees the NDS product is free from defects, or we’ll replace it.