When you start to plan, there is a sequence in which you should do things. First, check to see if your local government requires a well permit prior to drilling a well. Or, talk with your contractor about legal requirements to insure that the proper permits, if any, are obtained. You don't want to get started drilling and then get shut down because you did not pursue the proper channels first

You have to understand some basics of wells...when drilling a well, you are exploring to determine the quantity and quality of water available. Totally dry holes are uncommon, but low-yielding wells are more so. It is important to understand why wells are low yielding. Some causes of low yield include a low natural or seasonal water table, interference with other wells (for example, in a subdivision), and geologic conditions. You want to determine if there is a problem, or a potential problem with water yield before you actually put the well in.

If problems arise, the cost to repair them is less if you construct the well before you construct the house, because only the cost of the well is involved. Also, if a second well must be drilled, there is more likely sufficient space on the property if the house is not already there. If you are thinking about purchasing a property, have it checked out by a licensed and certified driller. If the driller feels like there is an area where adequate water supply is questionable, then you would be wise to get an option on the property rather than a straight out contract. That would be better, then you can get one with permission to have a well constructed first, and if the well fails, then you are not obligated to purchase the property.

There are some ways to tell if you are going to have a suitable well or not. The type of material beneath the ground surface in your area can tell you how successful you may be in obtaining a suitable water supply from a well. Your local drilling contractor will have experience in the area and should be able to tell you what to expect. Also, neighbors in the area should be able to tell you about quantity and quality if they have wells drilled on their property.
So once you determine if the water is a good quality, you need to determine if you have enough water. "Enough" water means sufficient quantity to meet the following needs... First, your everyday use: drinking, cooking, and water for "plumbing" (toilets, bathtubs, showers, automatic washers, dishwashers, and many other water using automatic appliances) Second, your seasonal use: lawn and garden watering, car washing, and swimming pool etc. Things that you do not use water for everyday, but things you use water for seasonally. Next, your specific and special uses: for example, animal watering, crop irrigation, and water treatment. Last but not least, while you may or may not ever meet this need, you will want have enough water for fire protection: this is a special need which you likely won't depend on a well.

Another thing to consider is that you have times during the day when you use a lot more water than during other times of the day. A day's use may be concentrated into a period of one to two hours, your well or water supply system must be able to meet this type of peak demand. A conservative estimate is that a home will need about 150-300 gallons per day for two to four people to meet all these needs.
So, find a location on your property that will support the use you need, and will be able to all year.