The main difference between spring, well and running water is the TASTE.
Spring water seeps from the ground, either a flat area or up a hillside. Springs can be dug out to promote flow of water. A spring on flat ground usually seeps through blue-gray clay when you dig down beneath the topsoil. A hillside spring will usually seep through brownish-red clay-like soil and makes an excellent source of fresh water because it is filtered through the soil, carrying slight amounts of minerals, and can be protected against polluting contaminants. If you dig into the hillside, making a small pool, then dig a small ditch to allow drain off, you can lay a plastic pipe in the ditch for drainage. We placed a couple of sandstone-type rocks under the end of the pipe, which we covered with a screen to keep any falling debris from plugging the pipe. Fill in the ditch to the upper level of the pool. Cover the pool with criss-crossed sticks, then a sheet of heavy-duty plastic. Next, cover with some of the dirt taken from the pool. Now you are ready to attach the other end of the hose to a large fiberglass tank for holding. There is your new water source for that cabin below the tank.
Well water comes in two basic types. Wells of long ago were hand dug at a fresh water source, lined with brick part way down, and water was bucketed up from the well. Usually these shallow wells were dowsed by a professional to locate the area where water was closest to the surface so they could be hand dug. As the water table drops during the year, so does the level in the open-top well. Over a period of time, if the surrounding area does not have a good spring system to feed this well, it may go dry. If a drought lasts for several years, you can be assured this well is apt to go dry during late summer or early fall. These types of wells are easily polluted, especially if an animal (or human) falls in and drowns.
Other wells are dug by machinery and usually have a six-inch casing. They are advantageous in that you can go down thousands of feet to a water source. Drillers prefer to go well below bedrock to insure a good water supply. There is where you can find hard water and water that is sulfuric, because of the minerals that are trapped that deep. Dowsing should be done to locate good tasting fresh water before drilling. A shallow well or deep well pump may be inserted and requires electricity to pump and bring the water to a surface storage tank. This is pressurized and fed into pipes that enter your house.
City water, which may be chlorinated and/or fluoridated, supposedly is good for you to drink as it is germ-free. This water source is usually from a large reservoir and is filtered through a treatment plant where it is "purified" for human consumption, then piped down to another plant for controlled delivery to customers. Most city water supplies are from this type of source.
Running water is found in streams and creeks. It is a good source for drinking as long as you know that no animals have polluted upstream. Another danger is giardia, which can be found in running water. It causes serious diarrhea for those who drink water that is polluted with this little critter. It doesn't seem to bother Bambi, though. But, I wouldn't want to drink from a stream where Bambi has been playing, either.