... /2HP, 110V, 20 GPM, 4" CE list Submersible Pump, Deep Well, 1/2HP, 110V, 20 GPM, 4" Features & Technical Specifications ... : 20 GPM. That is greater than almost all other well pumps.Solid stainless steel body with heavy duty cast iron dischargeIndustrial ... NPT dischargeDesigned to fit inside 4" ID or larger pipe/well casingHeavy-duty thermoplastic impellers, diffusers, and intake screen.High efficiency ...