Short answer to the question can a pool be installed if you have a well and septic tank on site: YES.
Each county has a requirement on the distance you need to be away from your well or septic. You need to check with your local building department to get this exact number.

An inground pool has its own plumbing system so it will not have to be connected to your plumbing. The water edge of the pool needs to be a certain distance away from the well and/or septic tank and drain field but in most cases; your pool patio would not have to be this distance away. Be sure you tell your pool installer where your septic tank and drain field are located.
The septic tank also has drain lines that can extend out 60 to 90 feet or more. You need to know where these lines are. If you have do not know for certain, you should contact your local building inspector or health department to see if they have a copy of your property’s plat. The plat should show you where the builder installed these lines. The plat will also inform you of any easements or other restrictions you will need to know about before beginning construction. The water edge of the pool also has to be a certain distance from these lines. Your building department can tell you those distance requirements.
The pool dealer you have contracted with to install your pool also should know these requirements. Your pool contractor can help you with locating your new pool on your property. Just remember, before doing any excavation, determine where your septic tank and drain lines are located. And one final point – always remember to call Miss Utility the required amount of time before you begin digging.