Where does our running water come from?

OMG. 

We use river water, ground water, and reservoirs to feed our water supply systems. There the water is treated by a variety of methods to reach certain standards of health and safety, it is then pumped into holding tanks or towers where it is delivered to the mains that supply our communities.

What you flush goes directly into sewer systems that go to waste water treatment plants that clean the water to a level that considered safe for our rivers to take down to the seas. This water evaporates and falls again as clean rain into our rivers and lakes where some of it is again cleaned for our use.

Water does get recycled, part of the process is by man and part of the process is by nature.

Now, we have some areas of the country that have millions of people too many for the water supplies that are available to them. If they choose to treat their sewage to drink it again, then that's on them, but the cost will be 30 times higher than what they pay now.

The first place was that the hydrogen and oxygen were formed by nuclear fusion in the star matter that became the earth.

With a cycle there is neither a beginning nor an end.  You can start at any point go through the cycle and get back to your starting point. It doesn't matter what use you put the water to you can follow it and eventually it ends up getting back into clouds and rain.

Now if we send it back to the ocean it is evaporated using the renewable energy of the sun.  Creating clouds and rain.

If we reuse the water before it reaches the ocean we must use energy. Much of which is NOT from renewable sources.  So we "save" water at the expense of destroying the planet.  Not a great solution.  In any case carrying our wastes away and dumping them into the ocean is a recipe for long term disaster in any case.  Unless the wastes themselves can be reused and recycled we are on a one way trip to nowheresville.

Depending on where you are, your tap water might come from wells or from surface water, mostly streams. A great deal of the latter has passed through a wastewater treatment plant upstream. During a drought (in PA), I added up the effluent volume from upstream of the water company's intake and found that it was very close to the volume of the stream at that point.

It all depends on where you live. Some will have it piped into their homes by a utility company who will have obtained in from a reservoir or extracted it from groundwater. You may live in a place where you have to walk several miles to collect water yourself from a river.

All of these sources will have obtained water as rainfall. As part of the cycle groundwater may eventually reach the surface again as the source of a river. water from rivers and oceans evaporates becoming water vapour in the atmosphere which will fall to earth again as rain.

Water you use at home whether it goes down the drain of a sink or the shower or is flushed from the toilet will eventually end up back in a river or an ocean.

It comes from the ocean.  The heat of the sun evaporates the water, which then falls as rain or snow on the land.  Some forms glaciers or snowpacks, but that eventually ends up in the rivers and lakes or the ocean to start all over again.

https://www.natgeokids.com/au/discover/science/nat...

It depends on where you live.  The main sources of drinking water (municipal water) are rivers or lakes (or dammed-up rivers to make a lake or reservoir).  Lots of places use groundwater though (get water from wells drilled into the ground), and lots of individuals get their house water from wells too (houses with no municipal supply).  Much less common for individuals to take right from a river or lake because that water will definitely need treatment.  Groundwater typically has already been treated by nature so does not need special treatment, although it can and does sometimes.

People with lake cottages that take water from the lake will use it to flush and even shower, but usually won't drink it (not if they are wise, at least).  There tend to be microorganisms in the water that can be a problem if you drink the water, but you can kill them with some treatment (dilute bleach works).

The interesting thing, of course, is that many cities on major rivers have always taken their drinking water from upstream of the city, and dumping the sewage downstream.  They tended to ignore the fact that upstream for them was downstream for someone else.  This is why we have such complicated systems for treating both our drinking water and our sewage.  It is way safer.  Cholera plagues aren't very fun, and dysentery isn't very pleasant.

That depends on where you are. Some water comes from water underground. In greater New Orleans it Moe's from the Mississippi River and Lake Pontchatrain