<p>This question has tenuous links to Earth Sciences, but the answer is simply that, historically, freshwater has been used to flush toilets, and hence the sewage treatment plants have been developed to treat non-saline sewage. The water can be (and frequently is) recycled for domestic use, whilst sewage sludge can be used to enrich farmland. No such benefits accrue to flushing effluent with saline water. It is then pollution, whether it is disposed of on land or at sea. </p>

<p>In many estuaries and deltas around the world sewage sludge does end up in the sea where it accumulates as tidal mud flats with an unnaturally high lipid content. Give this sediment a few tens of millions of years of compression and maturation and it will doubtless yield oil shale. </p>

CC BY-SA 3.0
2016-06-18T17:30:21.393Z
Good answer! Unfortunately the question is closed here, but it has been [cross-posted on Sustainability SE](http://sustainability.stackexchange.com/q/5354/99) where fits better. Would you consider posting your answer there as well?
THelper
CC BY-SA 3.0
2016-06-21T14:10:50.413Z
By all means, move Q&A.
Gordon Stanger
CC BY-SA 3.0
2016-06-21T17:36:35.320Z
Actually what I meant was; would you consider posting this answer yourself at the [same question posted on Sustainabiltiy SE](http://sustainability.stackexchange.com/q/5354/99). We can't move this question and answer there because the exact same question was already posted on Sustainability SE.
THelper
CC BY-SA 3.0
2016-06-18T13:45:01.493Z
2016-06-18T13:45:01.493Z
Gordon Stanger
<p>My question is in the header. It would seem to be a major environmental benefit if toilets used saltwater in stead of drinkable fresh water, right? </p>

CC BY-SA 3.0
2016-06-18T09:32:17.780Z
[Meta question](http://meta.earthscience.stackexchange.com/questions/1548/do-salt-water-toilets-belong-here-or-on-sustainability-se) about this one
Jan Doggen
CC BY-SA 3.0
2016-06-18T12:59:26.213Z
Not about Earth Science, but my guess is that you will need to build an entire water system (plumbing, infrastructure, etc) for salt water, in addition to fresh water. Then, I'm not sure there is any environmental or economical benefit. Some toilets use greywater, which is recycled water from laundry machines and dishwashers etc.
Gimelist
CC BY-SA 3.0
2016-06-18T13:06:42.243Z
And grey water can also be rain water. Grey water is of course more widely available (not in quantity, but in geographical area) then salt water.
Jan Doggen
CC BY-SA 3.0
2016-06-22T10:49:23.217Z
Please [do not cross-post](http://sustainability.stackexchange.com/questions/5354/why-dont-toilets-use-saltwater).
gerrit
<ocean><water><environmental-protection>
Why don't toilets use saltwater?
Slippers
# Why don't toilets use saltwater?

(Asked by: username_0 on 2016-06-18)

My question is in the header. It would seem to be a major environmental benefit if toilets used saltwater in stead of drinkable fresh water, right?

**Tags:** ocean, water, environmental-protection

> **Comments:**
> **username_1**: [Meta question](http://meta.earthscience.stackexchange.com/questions/1548/do-salt-water-toilets-belong-here-or-on-sustainability-se) about this one  
> **username_2**: Not about Earth Science, but my guess is that you will need to build an entire water system (plumbing, infrastructure, etc) for salt water, in addition to fresh water. Then, I'm not sure there is any environmental or economical benefit. Some toilets use greywater, which is recycled water from laundry machines and dishwashers etc.  
> **username_1**: And grey water can also be rain water. Grey water is of course more widely available (not in quantity, but in geographical area) then salt water.  
> **username_3**: Please [do not cross-post](http://sustainability.stackexchange.com/questions/5354/why-dont-toilets-use-saltwater).  

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## 1 answers

### Answer by username_4 on 2016-06-18. Score: 3

This question has tenuous links to Earth Sciences, but the answer is simply that, historically, freshwater has been used to flush toilets, and hence the sewage treatment plants have been developed to treat non-saline sewage. The water can be (and frequently is) recycled for domestic use, whilst sewage sludge can be used to enrich farmland. No such benefits accrue to flushing effluent with saline water. It is then pollution, whether it is disposed of on land or at sea.

In many estuaries and deltas around the world sewage sludge does end up in the sea where it accumulates as tidal mud flats with an unnaturally high lipid content. Give this sediment a few tens of millions of years of compression and maturation and it will doubtless yield oil shale.

> **Comments:**
> **username_5**: Good answer! Unfortunately the question is closed here, but it has been [cross-posted on Sustainability SE](http://sustainability.stackexchange.com/q/5354/99) where fits better. Would you consider posting your answer there as well?  
> **username_4**: By all means, move Q&A.  
> **username_5**: Actually what I meant was; would you consider posting this answer yourself at the [same question posted on Sustainabiltiy SE](http://sustainability.stackexchange.com/q/5354/99). We can't move this question and answer there because the exact same question was already posted on Sustainability SE.  

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