Yes, you can fill your ClearBlue mineral pool with any drinking water source.
Note that some well water has a high concentration of calcium, iron, sulphur and other contaminants. If this is the case, it is best to use a filter on the hose you are using to fill the pool.
Your pool & spa store or service can recommend the best filter after testing your water.
Note that we do not recommend using a stain & scale or sequestering chemical to remove contaminants from the water. These chemicals will remove the ClearBlue minerals from the water and you will have to increase the chlorine concentration to compensate.