Thanks for the science lesson.
Linda C

We have the same amount of water on Earth, it just cycles around, so the water you are drinking may have been drunk by a dinosaur one time!

Or peed by a skunk? EeEeewww!!

Al- it isn't the H2O, it's the accompanying ingredients that can stink. I can think of worse things than skunk which are nauseating in our water.

BTW, note how smoothly the mention of sources for recycling water is made in this article :)

Here is a link that might be useful: recycling H2O in space

Water that percolates down through the soil becomes purified by the silt and clay in the soil. Runoff water is not purified in the same manner. I think you are confusing ground water and underground aquifer.
Beneath the earth there are huge "reservoirs" of water....literally running streams in some locations. The one where I get my water is called The Ogalalla Aquifer. It is an amazingly large and pure water source.
At one time in the northern part of Iowa, there was a vast area of wetlands. The early farmers ( remember, we were fighting Indians here 150 years ago) drilled wells into the underground aquifer to drain the land. All well and good, but in the 1950's farmers began using excessive amounts of nitrates and herbicides and ir was entering the aquifer through the wells......so a campaign was mounted to plug them.
Water that enters the aquifer through soil percolation is largely cleaned of inpurities....but that which enters without being filtered is not.
Linda C

Knew that of course, but I wouldn't want to be in charge of separating the stink part from the water part. ;o)

My post was only a bit of levity. Forgive, if it wasn't funny, please.

Al

Al - I didn't chuckle -- I lol!

Linda - aquifers are not sealed-off chambers, with or without wells poked into them. Aquifer (even in the dictionary) simply means an underground area from which it is possible to obtain water. Aquifers "collect" their water from water which (eventually) has percolated down from the surface -- the waterdrops may have travelled sideways at some periods, just as some of the waterdrops may have taken eons to travel to the aquiferous level, but originally that water come from the surface. Soil porosity affects the speed of the water's downward travel, just as impermeability affects where there may an aquiferous layer.

Check the link for a nice explanation. BTW, did you know that there is considerable concern about the Ogalalla being depleted faster than it can refill? Not a minor imbalance-- a major depletion. Sigh.

Here is a link that might be useful: Aquifer definition