General Question

whitetigress's avatar

Where does water used from the faucet eventually go?

Asked by whitetigress (3129 points ) December 12th, 2011

I live in San Diego if that helps answer the question specifically for my region.

Observing members: 0 Composing members: 0

34 Answers

gailcalled's avatar

All water drains into pipes. In cities the dirty water goes to the sewage treatment plants. Google that for SD.

In the country, if you have a well like I do, the water drains into the septic tank; the solids sink to the bottom and have to be removed when you have the guy empty the tank every few years.

The liquid disperses into the leaching field and thence to the water table, where the cycle starts all over again.

Here ya go.

JLeslie's avatar

@gailcalled Having a well has nothing to do with having a septic system. I know you probably know that, but some people get confused so I thought I would mention it. I have city water, and a septic system for waste water.

gailcalled's avatar

@JLeslie: You can’t have a well without a septic system, but I suppose that you can have city water with or without one. Did you add your septic system for waste water rather than have it flow into city sewer pipes?

CWOTUS's avatar

All water is always recycled. Depending on the path it follows, that can take eons, or it can take days – even minutes. All water recycles.

Water falls from the sky as rain (or dew, or fog, or snow). The point is that water in the atmosphere eventually condenses into a form that causes it to precipitate to Earth.

If it falls in the ocean, lakes or rivers, then some of it is evaporated back into the atmosphere, and that “closes the loop” on its recycling, until the next time it falls.

If it falls on the poles, onto North Pole or South Pole ice, then it can be locked into that ice cap for thousands of years, but it eventually either falls off the ice shelf (Antarctica) or otherwise becomes an iceberg, melts into the ocean, and can continue the evaporation / condensing chain again.

Water that falls as fresh water on Earth can be “unused” in which case it may run off to the ocean again (eventually) or drain into the water table that underlies most surface land. This is often “mined” in the form of wells for human use in agriculture and human habitation.

Water that is used by humans and then drained through toilets, wash basins, bathtubs and various industrial processes is treated according to the needs (and laws and capabilities) of the users.

Industrial and some agricultural waste water often has heavy metals, toxins, fertilizer and other dangerous components that “normal” water treatment won’t resolve. This is often placed into “holding ponds” where the water can evaporate safely and the remaining solids can be concentrated for other treatment, disposal or use.

House drain water is normally treated in either municipal sewage systems, and the treated water (which is often cleaner than the drinking water you started with) is allowed to run off “normally” into lakes, streams and oceans, or it is used in agriculture, and then treated or run off according to that use. In the US and in much of the world, household waste water is drained into residential septic systems, where bacteria operate on the solids to dissolve and treat them, and the liquid waste (mostly water) seeps through the soil to the underlying water table. Septic systems are designed so that the water won’t seep through the soil faster than the soil can treat the waste, so that the water eventually reaching the water table is clean.

Water in the water table may stay there for tens of thousands of years, which is why depletion of huge aquifers is a potential problem for humanity’s future: it takes tens of thousands of years to build aquifers, too.

You can learn all of this and a lot more by researching “the hydrologic cycle”.

elbanditoroso's avatar

In my case (suburban Atlanta) is ends up back in the Chattahoochee River downstream, after having been filtered by the County. The Chattahoochee eventually meets and drains into the Appalachicola River, which drains into the Gulf Of Mexico.

JLeslie's avatar

@gailcalled Are we referring to the same well? I assume you mean well water for the faucets?

The lot my house is built on was able to connect to city water, but not the sewer system.

bkcunningham's avatar

Here you go:

The Department of Public Works (DPW) Wastewater Management Section (WWM) is responsible for maintaining sewer lines, pump stations, force mains and several treatment plants for the unincorporated areas of Alpine, Julian, Lakeside, Spring Valley, Pine Valley, Campo, East Otay Mesa and the Winter Gardens area. Wastewater flows originating within the communities of Alpine, Lakeside, Winter Gardens, Spring Valley and East Otay Mesa are transmitted to the City of San Diego metro system for treatment and disposal. The remaining communities of Julian, Pine Valley and Campo utilize “on-site” treatment and disposal systems.

This office also provides support services for other agencies such as County Parks, Sheriffs facilities and the San Pasqual Academy. The WWM office is also responsible for issuing sewer permits, plan checks for sewers, providing management and engineering services for capital and maintenance projects, sewer maps, billing, and general record keeping associated with sanitation districts managed and operated by the County.

Treatment Facilities


DPW operates and maintains six wastewater treatment facilities at Julian, Pine Valley, W.S. Hiese Park, Campo, Descanso Detention Facility, and San Pasqual Academy. These facilities serve as collection and treatment for final processing systems and do not transmit flow to the City of San Diego.


From the time wastewater enters any of the six treatment facilities it (influent) undergoes physical, biological and chemical treatment for many hours before the treatment process is complete. Treated water is discharged via controlled irrigation or percolation processes. Treatment plant operators are state certified.

Treatment facilities are complex and remarkably efficient when treating wastewater. The State regulatory agency permit demands that there be no detrimental impact on ground water.

The physical treatment process begins when the wastewater enters the plant through the headwork’s, passing through bar screens and grit removal basins. This initial treatment removes large, solid objects from the water that would otherwise disrupt the treatment process.

Next, the wastewater enters primary clarifiers where the flow is slowed to allow heavier, solid particles to settle and the lighter solids to float.

Biological treatment involves sending wastewater through advanced secondary treatment processes, which utilize aeration basins to remove 90–95% of the suspended solids and dissolved organics. Biological treatment also removes most of the organic nutrients. Secondary clarifiers enable additional settling of solid materials before the final treatment stage of disinfect ion. Solids separated during the process, commonly called sludge or bio-solids, undergo a stabilization process by aerobic digestion. The sludge (bio-solids) is dried in adjacent containment beds, stored in covered containment structures, and finally disposed of after testing in a sanitary landfill.

Operational checking and laboratory testing are required to effectively document the quality of treatment. The results are reported quarterly to the State Water Quality Control Board (SWQCB).


Upon completion of the treatment processes, the cleaned water (effluent) is chlorinated and then pumped to storage basins or percolation beds. Julian and Descanso irrigate the surrounding land. Rancho Del Campo, Pine Valley, and Hiese Park use percolation beds.

YoBob's avatar

Excellent question.

In most cities it goes to the same place that all of the other waste water does. All of it is treated as sewage and is given the same treatment at the sewage treatment plant.

There are some more modern homes these days, in an effort to be more environmentally friendly, that collect the “grey” water (that’s anything other than water from the toilet) in storage tanks to be used for watering the lawn.

gailcalled's avatar

@JLeslie: So if I have this straight, you have pipes coming into the house with city water (from the reservoir) but pipes going from the house to your septic system.

You are paying for both city water and regular cleaning of your septic tank then? They got you coming and going?

JLeslie's avatar

@gailcalled I pay for city/public water coming in. I don’t pay anyone for my septic, that has nothing to do with the city, that is my own system. I don’t see how that is coming and going?

gailcalled's avatar

Do you have to pay to have the septic system drained and cleaned every few years? I do it here once every five years since I live alone most of the time.

JLeslie's avatar

@gailcalled I never have. The system/house is about 9 years old.

JLeslie's avatar

@gailcalled Does the city make you do it?

bkcunningham's avatar

@gailcalled, do you use yeast or some other commercailly marketed product in your toilets to help your septic tank? How big is your septic tank?

gailcalled's avatar

I don’t live in a city but a rural hamlet. If my septic system and tank back up and leak or break, I am the only one responsible..

@JLeslie; Perhaps after nine years you might want to consider having it emptied.

@bkcunningham: I cannot remember the size, but I use no commercially marketed products. The plumbers and builders (including my brother-in-law) strongly advise against anything but emptying it.

Two years ago I had to replace the pipe from the house to the tank. It was seriously bending and about to break. The replacement pipe is much stronger and will outlast me.

JLeslie's avatar

Back to the question, there are some cities that clean sewage water and it goes back into the drinking system. Orange County is an example.

@gailcalled I’ll look into it, I didn’t know I had to worry about it. I thought ht ebacteria was supposed to take care of everything. Thanks.

gailcalled's avatar

@JLeslie : “Inspect and pump frequently From the EPA

You should have a typical septic system i*nspected at least every 3 years* by a professional and your tank pumped

￼Inspection Include:

• Locating the system.
• Uncovering access holes.
• Flushing the toilets.
• Checking for signs of back up.
• Measuring scum and sludge layers.
• Identifying any leaks.
• Inspecting mechanical components.
• Pumping the tank if necessary.

CWOTUS's avatar


Most properly sized and properly used residential septic systems can be used for years with zero maintenance. It’s not unwise to do what you do every so often to ensure that sludge doesn’t accumulate to the height of the baffles, but in most cases that won’t happen anyway.

When the sludge accumulates to the height of the baffles, then solids pass out into the leach field, eventually rendering that useless. At that point, repair becomes problematic and expensive because:
A. The septic tank needs to be opened and pumped out thoroughly and on an “emergency” basis. (Which means that the yard has to be dug up, the whole top of the tank removed, and all of the sludge cleaned out.)
B. The leach field also requires major repair or replacement, since its effectiveness will have been limited (maybe for several years) by the excess effluent.

Pumping the tank on a normal basis only involves uncovering an [edit: not “and”] inspection / pump opening (not the whole tank top) and pumping out by a hose. This means the yard doesn’t get torn up, the process can be scheduled at a convenient time, and the expense is minimized.

gailcalled's avatar

True. I never tear anything up. But I feel best if the guy and his truck and pump comes out every five years. I have enough trouble with surprise things that go wrong; being both the lady of the house and the guy in charge, I try to minimize catastrophes.

Perfecty put: vv.

“Pumping the tank on a normal basis only involves uncovering and inspection / pump opening (not the whole tank top) and pumping out by a hose. This means the yard doesn’t get torn up, the process can be scheduled at a convenient time, and the expense is minimized.”

JLeslie's avatar

@CWOTUS @gailcalled I’ll call the guy who installed the system and see what he says, or what he charges for the inspection pump thingy. I talked to him once, he gave me some packets of stuff to put into the system. He never said I have to get it pumped every 5 years. The house is rather large and only two of us live here, and I am not obsessive with cleaning productd. The first people who lived here was a couple with two little kids. They were here for two years.

john65pennington's avatar

Simple answer. Faucet water is just like all other used water in your house. And, this includes water from the shower and commode. It reverts right back to its origination point or destination, the water prosessing plant. Is it faucet water used over and over again? Most likely, yes. Rainwater and dinosaur rements are added into the mix, along with chlorine and germ-killing agents and its recycled agan.

This is why I never drink faucet water. I have no choice but to take a shower in my recyled, polluted water.

The faucet water you used today, is probably the same water you used last week, to flush your commode.

Kind of makes you sick when you think about it.

gailcalled's avatar

@john65pennington: Move out of town and dig a well. My water is delicious, and to quote the guy who did the tests for me (in an unfortunate turn of phrase), “It is water to die for.

JLeslie's avatar

@gailcalled But, you’re in NY right? If my memory serves. NY has fantastic water. Not all states do.

CWOTUS's avatar


Not at all! Not one bit! It might be the same municipal utility running the “Water & Sewer Department”, but the facilities are not at all ‘the same’! Absolutely not, never. Although the water that is allowed to finally leave the sewage treatment plant may be drinkable. Even so, for political / marketing reasons – and because we’re not that desperate for fresh water in the first world – it won’t be, at least for now.

JLeslie's avatar

@CWOTUS You are probably right where @john65pennington lives, but did you see my link for Orange County? They do have a facility that purifies waste water and puts it back into the pipes for drinking.

CWOTUS's avatar

Thanks, @JLeslie. I hadn’t seen it earlier. That’s a good example of what’s in our future, but even that doesn’t ‘pipe’ the effluent water to drinking water pipes. The final filtration step is to allow the effluent water to percolate through the ground, same as rainwater does. It’s amazing how much cleaner “dirt” can make our water, isn’t it?

Some other experimental treatment plants (which may be operational on large scale now; it has been awhile since I saw the prototype / model plant) is to create an artificial wetland at the end of the treatment process. The effluent water supports a lot of plant life, algae and waterfowl and fish, and the water is filtered through the plants, which are also harvested for livestock feed. (In colonial New England the salt marshes were harvested for free fodder in the same way.) The water running out of the artificial wetland runs into a river – cleaner than the water it joins.

gasman's avatar

@gailcalled, @JLeslie: In 1994 we built a house in semi-rural Georgia that had municipal water but no sewer system—everyone had septic systems—and as of 2007 that region still had no sewer. The same was true in the late 80s in parts of Rancho Santa Fe, CA—a hilly suburb of San Diego—where some lots needed septic systems but all had a water supply. It seems that sewer systems are rather expensive infrastructure, probably because handling big pipes and digging trenches for them is a big job, compared to laying down comparatively thin water lines.

LostInParadise's avatar

In the case of San Diego, I would think that nearly all the water eventually finds it way to the ocean.

JLeslie's avatar

@gasman Yeah, it isn’t very uncommon. I prefer having public water actually, even though it has a bunch of chemicals in it. Across the street from me the houses have sewer.

SmashTheState's avatar

@john65pennington I was fishing off the sea wall in Vancouver, once, for my dinner, when a female jogger stopped to look in my bucket. She saw the fish I had already caught (a couple of bullheads and a cod — I go for the easy fish, not the “challenging” fish) and asked me if I actually eat what I catch. I agreed that I did, and she made a face.

“Don’t you know the waste treatment plant is just around the bend?” she said, wrinkling her nose.

Rolling my eyes, I replied, “Lady, I’m not eating shit. The fish eat the shit, and the shit becomes more fish. That’s how it works.”

She was unconvinced and left me to my fishing. The fact is, if you eat any of the bottom-feeding fish like cod, catfish, flounder, breem, et al., then you’re eating recycled shit. And since most other fish eat those fish, you’re at best just one step farther away. Every drop of water in the ocean has been piss at some time or another. If the idea of eating molecules which were once part of shit, piss, snot, semen, corpses, or Andy Dick bothers you, then I hope you plan to take up a breatharian lifestyle, since there’s not a goddam thing on Earth you can eat.

CWOTUS's avatar


I think Carl Sagan’s metaphor that “we are all star dust” was perhaps more poetic, but your assertion that “we are all shit” is equally true.

submariner's avatar

I live in Michigan on the coast of Lake Michigan. My drinking water comes from the lake. The water that goes down the drain goes to a wastewater treatment facility, and then is dumped back into the lake. At least I think that’s how it works around here.

There was actually a discussion of water usage on NPR’s “Talk of the Nation” the day this thread was posted, and it got me thinking. Do I really need to be all that careful with water? If I leave the water running while I brush my teeth, the water just goes right back to the lake that it came from. I have to pay for it, since it is metered, but I’m not depleting a well or other source. Am I mistaken about this?

CWOTUS's avatar

In your case, @submariner, there are a couple of things to consider:
1. You probably aren’t paying the full price of the water directly. That is, most municipal water works are subsidized in some form by the state and even federal governments. So we all have a tiny share of the cost of your water. Sewer, too.

2. Sewage treatment plants have to be designed with excess capacity. Since the plants are generally designed and built with an expectation of a minimum 40-year operating cycle (and generally operated far beyond that, too), they have to be designed, built and maintained with some amount of reserve capacity. Otherwise, you’ll start hearing about more and more frequent – and severe – instances of overflow of raw sewage directly into the lake. And when I lived in the Benton Harbor / St. Joseph area between 20 and 10 years ago, this was not an occasional occurrence. So all of the excess water you run – whether it’s clean or not when it hits the drain – adds to the “treatment capacity requirement” and takes the waste treatment plant that much farther along the road to obsolescence and replacement, or disastrous overflow.

3. Aside from those two factors, even if you were paying the full price, and even if you were 100% responsible for your own wastewater disposal, and those costs too, it’s still “waste”. If you’ve really been in the silent service, then you already know the limitations of living in a closed system and the need to limit waste.

submariner's avatar

^I haven’t really been in the silent service (I got the idea for my username from Fluther’s masthead art), but those are good points anyway.

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