Relationship ​between NRW and UF Water

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I do research ​in the field of ​water policy so ​I would like to precisely ​understand ​the relationship ​between non-​revenue ​water (NRW)​ and unaccounted-​for water (UFW)?.

What is the ​difference ​between UFW and ​NRW?  ​

Could you ​please give ​some illustrative examples?

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14 Answers

  1. Interesting topic,I once work with the government and the same question was ask but I now understand the difference ( NRW ) is water that is being produce minus usage and not being charge and unaccounted-for water is leakage which is not being reported and not action resulting lost of production

  2. The Water ​Network ​research team ​has consolidated ​an answer to ​the above ​question.  ​
    Further input ​from members is ​welcome and ​appreciated. ​   


    Water loss is water that never reaches the customer. Water loss has impact on profitability and water quality.

    Water loss greatly affects operational costs and treatment.

    Non-revenue water is the water that is lost before it reaches the customer. Losses can be real or apparent.

    Water Loss

    Physical Loss (Real Loss)

    Commercial Loss (Apparent Loss)

    Pipe breaks and leaks

    Metering errors

    Storage overflows

    Water theft

    House connection leaks

    Billing anomalies

     

    · Apparent losses are non-physical losses in utility operations due to meter inaccuracies, data handling errors in billing and unauthorized consumption.

    This is water that is consumed but not properly measured, accounted or paid for.

    · Real losses are physical losses such as leakage and storage overflows.

    This water never reaches the consumer , but it inflates the water bill since this water is treated but unused.

     

    According to the World Bank, in most developed countries there are no or insignificant water losses, but in developing countries it is estimated that, for example, illegal connections are about 40% of non-revenue water.

    Validating water audits requires testing the production water meters and testing a random sample of customer meters, excluding the system errors in billing and eliminating illegal connections.

     

    Non-revenue water (NRW) includes authorized unbilled consumption (such are water use by firefighters and religious institutions).

    Non-revenue water is the difference between the volume of water delivered in a network and billed authorized consumption.

    Unaccounted-for water (UFW) excludes authorized unbilled consumption.

    Unaccounted-for water is the difference between the volume of water delivered in a network and legitimate consumption, both metered and unmetered.

     

    System Input Volume

    Authorised Consumption

    Billed Authorised Consumption

    Billed Metered Consumption

    Revenue Water

    Billed Unmetered Consumption

    Unbilled Authorised Consumption

    Unbilled Metered Consumption

    Non-revenue Water

    Unbilled Unmetered Consumption

    Water Losses

    Apparent Losses

    Unathorised Consumption

    Metering Inaccuracies

    Real Losses

    Leakage on Transmissions and Distribution Mains

    Leakage and Overflows at Utility Storage Tanks

    Leakage on Service Connections


    Read more about water losses in our article - here. 


    Sources:

    1 Comment

  4. George, most of the answers here are correct. In summary the difference between NRW and UFW is that NRW consists of known and unknown water consumption that are not billed/invoiced/can not be paid for while UFW costs of unknow water consumption only. You can google and read further work on the same from Sharma (2008) as well as Sharma (2014) that clearly define and illustrate the two.

  5. Some good answers here but how to know which one is correct. In my understanding 'UFM' meant any water which was not accounted for in a physical sense rather than anything to do with finance. 'NRW' means any water which has been produced but not paid for . It would thus include the small loss of revenue which has been billed but the income not collected. There was a diagram produced by one of the water organizations showing how the various components added up to make UFW and NRW but I can't find it now. The unfortunate thing is that many of the donor agencies (eg DfID) have treated them as the same thing and set unreasonable targets based on a misconception.

    1 Comment

  7. Non revenue water (NRW) is water that has been produced and is “lost” before it reaches the customer. Losses can be real losses (through leaks, sometimes also referred to as physical losses) or apparent losses (for example through theft or metering inaccuracies). High levels of NRW are detrimental to the financial viability of water utilities, as well to the quality of water itself. NRW is typically measured as the volume of water "lost" as a share of net water produced. However, it is sometimes also expressed as the volume of water “lost” per km of water distribution network per day.

    UFW =NET PRODUCTION - LEGITIMATE CONSUMPTION

    NRW =NET PRODUCTION - REVENUE WATER

     

        = UFW  + WATER WHICH ACCOUNTED FOR, BUT NO REVENUE  IS COLLECTED (UNBILLED  AUTHERIZED CONSUMPTION)

    1 Comment

  8. Dear George, In 2003, Non-Revenue Water (NRW) in a water distribution network, which has been introduced by the IWA instead of Unaccounted For Water (UFW). For your information, BR, Wu Hao

  9. Another way of thinking about NRW is that it is the sum of physical losses and commercial losses. Also NRW is normally expressed as a percentage, so NRW = (Distribution input - billed volume) x 100 / distribution input

    1 Comment

    1. The International Water Association (IWA) strongly advises against the use of NRW as a percentage for target setting. It is still frequently used as a percentage in reporting - especially to non-engineers. It should be understood that the % of NRW is dramatically affected by the annual volume of consumption and so is unreliable for target setting.

       

      There are many references for this, here are some.

      Who says %s by volume are unreliable?:

      UK ‘Report 26’, 1980

      German DVGW, Note Paper W391, 1986

      UK ‘Managing Leakage’, 1994

      American WWA Leak Detection & Water Accountability Committee, 1997

      OFWAT, UK Economic Regulator, 1997

      South African Bureau of Standards, 1999

      Malta Water Services Corporation, 1999

      New Zealand Water & Waste Association 2001

      Water Services Association of Australia 2003

      German DVGW, Note Paper 392, 2003

      World Bank Institute 2005

      Austrian OVGW 2009

       

      I hope this helps.

      Stuart

  11. according to IWA guidance , Non Revenue Water (NRW) is the volume obtained by deducting Billed Authorized Consumption from system Volume.

    Unaccounted For Water (UFW)  is the volume obtained by deducting Billed  AND UNBILLED Authorized Consumption from system Volume.

    UFW is a part of NRW out of Unbilled Authorized Consumption ( like fire hydrants or water used for cleaning the network). In other words, UFW = net production – legitimate consumption.

    best regards,

  12. they are closely relalated, UFW is water that is lost due to leakages ,water theft and it is not known where it have gone. at the same time NRW is water that is lost the same as unaccounted water and some water that is known where it has gone bt not being paid for, for example water that is taken from metered stand pipes and delivered by bulk tankers to provide vulnarable societies and is not being paid for

     

  13. UFW- leakages in rising mains and distribution system before the water reaches the meter of consumer

    NRW-drawl of water from tubewells including handpumps

     

  14. Dear George, UFW clarifies the difference between water delivered in the network and the actual usage, whether it is metered or not (like fountains, fire hydrants of free deliveries to hospitals or some public facilities). 

    The NRW ratio refers to water delivered in the network but it only compares it with the invoiced volume.

    The main difference between both indicators is that UFW considers the volume of water that does not generate any income.

    In some countries, like in Indonesia, where I leave, the challenge is to consider the illegal connections and damages on meters that hamper a proper billing.

     

    best regards 

    1 Comment

    1. Dear Mr. George,

      I'm providing below links to 4 publications that will make you "expert" in the field:

      The Issues and Challenges of Reducing Non-Revenue Water

      Rudolf Frauendorfer Roland Liemberger, 2010

      https://www.adb.org/sites/default/files/publication/27473/reducing-nonrevenue-water.pdf

       

      ADB Assistance to Water Supply Services in Metro Manila

      https://www.oecd.org/countries/philippines/42229254.pdf

       

      Urban Water Supply and Sanitation in Southeast Asia A Guide to Good Practice

      Arthur C. McIntosh, 2014

      http://www.pseau.org/outils/ouvrages/adb_urban_water_supply_and_sanitation_in_southeast_asia_a_guide_to_good_practice_2014.pdf

       

      Non Revenue Water Reduction Strategy in Urban Water Supply System in India

      RR Dighade, MS Kadu and AM Pande, 2015

      International J. of Research in Engg and Applied Sciences

      http://mgijournal.com/cur_issue/4.pdf