Basically, under a normal local water district condition, with * 2” inlet and outlet manual head can deliver a greater volume of water (about 12–18 GPM-gallons per minute/or approximately 17000 to 26000 GPD- gals. Per day) While the ** with 1” inlet and outlet manual head can deliver up to 6 to 9 GPM- GPM-gallons per minute/or approximately 8000 to 12000 GPD- gals. Per day. Note: It should be understood that the above estimated volume of water are measured based on what is going to be delivered at the product tank/reservoir and not in every faucet’s end. Thus, GPD’s usual factor in increasing its GPD is the size of a pipeline. *With 2” inlet and outlet manual head) can only deliver 6 to 9 GPM- GPM-gallons per minute/or approximately 8000 to 10000 to 12000 GPD- gals. Per day if the pipeline is only 1”. (from the source up to the product tank or reservoir) **Nonetheless, even when you have 2” pipeline, if we apply the proposal 1, we still get the same result of 6 to 9 GPM- GPM-gallons per minute/or approximately 8000 to 10000 to 12000 GPD- gals. Per day. If the pipeline is only 1”.(from the source up to the product tank or reservoir) Please take note ; that under normal local water district condition, your current water production can not in anyway be affected by any of our chosen equipment.