Hi @zj202021009 , I know this is a tricky problem to solve. I have confirmed that two of the rasters that you shared contain pixels with nan values, and those are likely the cause of the nan values in the water production results. The two files are:
2020Pre.tif
3741 pixels with nan
2020Pre1.tif
3741 pixels with nan
If you can reclassify those pixels to something else, such as the NoData value of the raster, then I expect that will solve the problem.
Best,