Separation of drinking water from other domestic consumption

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There is plenty experience on conventional dual water systems which usually refer to separation of potable (drinking, bathing, dishwashing,…) water from non-potable (toilet, irrigation, ...) consumption. However, separation of drinking water solely from the other domestic consumption (i.e. bathing, dishwashing, laundry, toilet flushing and…) has rarely been reported. This kind of "non-conventional dual water system" might be used when quality of available water does not meet required standard of drinking water but can be accepted for other domestic consumption.

Suppose Nitrate or TDS level in a water network is higher than the drinking standard value. Therefore, the water cannot be used for drinking but might be acceptable for the other indoor consumption like bathing. In this case, using the "non-conventional dual water system" could be recommended. In this regard, the following questions might be raised:

-  What is minimum water quality for domestic consumption except for drinking (including cooking)?  Does any standard exist for this? On the other hand, standard levels (e.g. WHO Guidelines for Drinking-water Quality, 2011) of which drinking water quality parameters can be reduced for bathing and dishwashing consumption?  

- What would be the impacts (e.g. operational, economic, social, and environmental) and associated risks, if this kind of dual water systems would be used?

- Do you know any city or rural area in which the "non-conventional dual water system" has been used? 

If anybody has some information or can address some references about this kind of dual water systems, please kindly mention. I shall be most grateful to receive any comments in this regard.  

7 Answers

  1. The use of water meters was not made compulsory in the Uk because of the fears that the poorer people would avoid using it because of cost.

    In the 19th century the real concerns were for contamination of conventional water supply e.g. rivers, wells etc. The 1854 cholera outbreak had a good deal on influence on sewage but it also lead to greater investment in potable water supplies including the Royal Family's Sandringham estate which supplied the locals (the King or Prince of Wales was also infected). https://en.wikipedia.org/wiki/1854_Broad_Street_cholera_outbreak

    As to the use of dual water, those with metered mains supplied water still continued to use rain water for other uses. There are a number of studies made in the 19th century which are detailed in a paper given to the Institute of Engineers in 1882 By J J Tylor which is to be found on the internet. Over time people have come to use potable water for everything from washing and bathing to watering the garden and filling fish ponds. OK when their is adequate supply but we also see more use of interceptors in rainpipes to gather rainwater for garden use.  Rainwater is probably as clean as it gets. Ground abstraction licences (in the UK) are strictly controlled and new ones hard to get.

     

    1 Comment

    1. Thank you Jon for your comment. Would you please give me complete address of the paper written by J J Taylor? I could not find it on the internet. 

      Commented on by

      1 Comment reply

  2. French English

    Bonjour 

    Bien entendu quer tout peut se faire. Simplement on va augmenter la proportion de la pollution dissoute qui risque d'arriver dans un endroit ou ce liquide servira à l'hygiène, l'alimentaire, beaucoup trop dangereux 

    En plus d'un facteur néfaste de se retrouver dans un liquide subissant un traitement X ou Y mais dont l'importance d'efficacité serait trompé 

    Non conseillé 

     

    Hello of course explain everything can be done. Simply we will increase the proportion of the dissolved pollution that will happen in a place or this liquid will be used to hygiene, food, far too dangerous in addition to a vicious cause to be in a liquid undergoing treatment X or Y but the importance of efficiency would be mistaken not advised 

    1 Comment

    1. Many thanks Marius for your comment. 

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  3. The Drinking water and Wastewater are separated all the time. As we know that water cycled from waste to portable, and from portable to waste. You need to understand Waste Safety Plan and Wastewater Risk Abetment Plan. WSPn is for Drinking Water while W2RAP is for wastewater.  Then is where you can get answer there.

  4.  

    Dear Igor

    Thanks for your reply.

    I really need results of those investigations on real health studies.  Does any standard or guideline exist for this? If you or others have some information or can address some references about such investigations, please kindly mention.

    Answered on by

  5. Hi

    Considering crucial situation of water resources, I assume it is important to recycle water for non-potable uses. On the other hand, as you may know, a considerable amount of money are being spent on providing a high quality potable water, which majority of it won't be used for drinking. 

    To wrap up, I think it is necessary to separate drinking water consumptions from the other uses of water. 

    I have seen some standards and guidlnes in this regard, and I will email them to you. I hope it could be useful.

    Regards

    Davoud

    1 Comment

    1. If it is no trouble, please send it to me also. Thank you...

  6. Dear Igor,

    Many thanks for your interestinganswer.

    It should be noted that dual water system is not necessarily dual water network.

    In the case that quality of available water does not meet required standard of drinking water but can be accepted for other domestic consumption (e.g. bathing, dishwashing, …) people may use bottled water or take drinking water from local water kiosks, or may use domestic water treatment  plant to provide  water for their drinking (and perhaps cooking) need. In all mentioned cases drinking water is separated from other domestic consumption by a "non-conventional dual water system".

    Based on this definition, many cities and villages use non-conventional dual water system. For example in some cities and villages in Asia and Africa, where  TDS or Nitrate level of network water is higher than the drinking standard value, drinking water is distributed by local water kiosks and the lower-quality water of main pipe network is used for other domestic consumption (e.g. bathing, dishwashing, …). In this case, main concern is not about drinking water but about using the non-drinking part which obviously doesn’t have quality of water drinking standard (e.g. WHO Guidelines forDrinking-waterQuality, 2011).

    Suppose people take shower with water which has high level of Nitrate or TDS value, is it dangerous for their health in short or long time? Does anystandard of water quality exist for this? Same questions exist about water quality of dishwashing.  

    Answered on by

    2 Comments

    1.  

      Dear Igor

      Thanks for your reply.

      I really need results of those investigations on real health studies.  Does any standard or guideline exist for this? If you or others have some information or can address some references about such investigations, please kindly mention.

      Commented on by

    2. Showering with water with high level of Nitrate, based on drinking water quality values is dangerous like swimming in lakes, rivers, seas, mineral water spa's, etc. Based on my experience and investigations some levels are determined based on real health studies and some are based on precautions. There is something in human psychology when they open a tap, they are scared what kind of water is coming out, but in fact, some water companies bring more effort to distribute healthy water then some bottled water companies and distributors, which is now a different discussion :)

  7. Dear M Jalili, let me answer some of your questions.

    1. European Union has it's own legislation regarding drinking water quality. The Drinking Water Directive (Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption) concerns the quality of water intended for human consumption. You can easily search online for all the parameters, explanations, etc.

    2. Drinking water business is one of most growing businesses in the world today. As everything is driven by the money, so is this topic. If we calculate good investment return period and economic benefit, there would be investors interested in this solution. But, I remember a case from some decade or two ago, when an automobile tires company put into market a non-inflation car tire which cant blow as there is no air in it. But, it didn't find its place on market as tire services didn't have equipment for it's installation, didn't want to invest in it - train it's stuff, etc., and the idea broke down. I see your case similar to the tire example I gave. There need to be a huge change in domestic installation services provided by plumbers, big change in utility companies, and so on. But again, if there is a good case for it, if water production price is high enough so you can make big savings and afford doubling the network, why not.

    3. No :)

    Best regards and please continue whit this kind of interesting discussions.

    1 Comment

    1. Dear Igor,

      Many thanks for your interesting answer.

      It should be noted that dual water system is not necessarily dual water network.

      In the case that quality of ​​available water ​​does not meet ​​required ​​standard of ​​drinking water ​​but can be ​​accepted for ​​other domestic ​​consumption (e.g. bathing, dishwashing, …) people may use bottled water or take drinking water from local water kiosks, or may use domestic water treatment  plant to provide  water for their drinking (and perhaps cooking) need. In all mentioned cases drinking water is separated from other domestic consumption by a "non-conventional dual water system".

      Based on this definition, many cities and villages use non-conventional dual water system. For example in some cities and villages in Asia and Africa, where  TDS or Nitrate level of network water is higher than ​​the drinking ​​standard value, drinking water is distributed by local water kiosks and the lower-quality water of main pipe network is used for other domestic consumption (e.g. bathing, dishwashing, …). In this case, main concern is not about drinking water but about using the non-drinking part which obviously doesn’t have quality of water drinking standard​ (e.g. ​WHO ​Guidelines ​for ​Drinking-​water ​Quality, ​2011).

      Suppose people take shower with water which has high level of Nitrate or TDS value, is it dangerous for their health in short or long time? ​​Does any ​​standard of water quality exist ​​for this? Same questions exist about water quality of dishwashing.