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Surveys on Water Supply and Sewerage

• 1Contact
  • 1.1Contact organisation
    National Statistics Institute of Spain
    
  • 1.5Contact mail address

    Avenida de Manoteras 50-52 - 28050 Madrid

    
    
• 2Metadata update
  • 2.1Metadata last certified
    30/08/2022
  • 2.2Metadata last posted
    27/07/2022
  • 2.3Metadata last update
    30/08/2022
• 3Statistical presentation
  • 3.1Data description

    The main objective of the survey is the study of the of the variables that make up the so-called "integral water cycle" (abstraction, supply, sewage, treatment of wate water).

  • 3.2Classification system
    • Clasificaciones utilizadas

      National Classification of Economic Activities (CNAE-2009)

  • 3.3Sector coverage
    • Division 36: abstraction and water supply of CNAE-2009.
    • Division 37 : collection and treatment of waste water of CNAE- 2009.

     

  • 3.4Statistical concepts and definitions
    • Amounts invoiced to users for water services
      All the concepts paid by users for the water supply, sewerage and wastewater treatment. It does not include the invoiced VAT.
    • Sewerage system
      Service for collection and directing wastewater to filtering or dumping sites. Information is required regarding the number of spillways in the sewerage system, as well as the number and total capacity of the storm tanks.
    • Supply/distribution of outgoing treated water
      This is the volume of treated water registered and not registered. The water registered is the measurement in the metres of the users, and distributed as outgoing to the different users (household, agriculture, industry, services and municipal consumption). The water not registered is that whose volume is estimated, gauged or not measured.
      The water not registered is broken down into real and apparent losses.
      - Real losses: these are the physical water losses that occur in the public supply network, up to the measurement point of the user. They include water leaks, breaks, overflows and breakdowns in the distribution networks and in user undertakings.
      - Apparent losses: these are the non-physical water losses. These are due to the inaccuracy of the metres, unmeasured authorised consumption and unauthorised consumption (fraud).
    • Water collection
      This consists of extracting water from nature. This includes both the water collected through the granting of the corresponding River Basin District, and that collected from ones own resources.
    • Water Supply and Sanitation Unit (USSA)
      The set of activities relating to the integral water cycle, which a local group, entity or company manages within the area of a single Autonomous Community.
  • 3.5Statistical unit

    The observation unit is the so - called Unit of Supply and Sanitation of  Water (USSA) comprising the activities relating abstraction, supply of water in detail and treating of wate water, that a company or institution manages in the same autonomous community.

  • 3.6Statistical population

    The population scope is all units rendering services classified in the divisions 36 and 37 of CNAE-2009.

     

  • 3.7Reference area

    The survey covers the entirety of the national territory.

    The utmost disaggregations of the survey estimations is the region ( NUTS II )

  • 3.8Time coverage

    The survey is carried out annually until 2016, biennally after this year.

     

  • 3.9Base period

    The first results from the survey were published in reference to the year 2006.

• 4Unit of measure
  • 4.1Unit of measure

    The unit of measurement for the water volumes is : thousand of cubic meters

• 5Reference period
  • 5.1Reference period

    The reference data is annual and the survey is carried out in a biennal period.

    Data referred to the period: Bienal 2020

• 6Institutional mandate
  • 6.1Legal acts and other agreements

    The compilation and dissemination of the data are governed by the Statistical Law No. 12/1989 "Public Statistical Function" of May 9, 1989, and Law No. 4/1990 of June 29 on “National Budget of State for the year 1990" amended by Law No. 13/1996 "Fiscal, administrative and social measures" of December 30, 1996, makes compulsory all statistics included in the National Statistics Plan. The National Statistical Plan 2009-2012 was approved by the Royal Decree 1663/2008. It contains the statistics that must be developed in the four year period by the State General Administration's services or any other entity dependent on it. All statistics included in the National Statistics Plan are statistics for state purposes and are obligatory. The National Statistics Plan 2021-2024, approved by Royal Decree 1110/2020, of 15  December, is the Plan currently implemented. This statistical operation has governmental purposes, and it is included in the National Statistics Plan 2021-2024. (Statistics of the State Administration).

    
    

    The survey gathers information regarding the different water uses, is included in National Statistical Plan 2017-2020, as statistical operation nª. 7111, known as the "Statistics on water supply and sanitation".

  • 6.2Data sharing
    The exchanges of information needed to elaborate statistics between the INE and the rest of the State statistical offices (Ministerial Departments, independent bodies and administrative bodies depending on the State General Administration), or between these offices and the Autonomic statistical offices, are regulated in the LFEP (Law of the Public Statistic Function). This law also regulates the mechanisms of statistical coordination, and concludes cooperation agreements between the different offices when necessary.
    
• 7Confidentiality
  • 7.1Confidentiality - policy

    The Statistical Law No. 12/1989 specifies that the INE cannot publish, or make otherwise available, individual data or statistics that would enable the identification of data for any individual person or entity. Regulation (EC) No 223/2009 on European statistics stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society

    
    
  • 7.2Confidentiality - data treatment
    INE provides information on the protection of confidentiality at all stages of the statistical process: INE questionnaires for the operations in the national statistical plan include a legal clause protecting data under statistical confidentiality. Notices prior to data collection announcing a statistical operation notify respondents that data are subject to statistical confidentiality at all stages. For data processing, INE employees have available the INE data protection handbook, which specifies the steps that should be taken at each stage of processing to ensure reporting units' individual data are protected. The microdata files provided to users are anonymised.
    

    The data of rhe autonomous cities of Ceuta y Melilla are published jointly to avoid the identificacion of the respective one company.

• 8Release policy
  • 8.1Release calendar

    The advance release calendar that shows the precise release dates for the coming year is disseminated in the last quarter of each year.

    
    
  • 8.2Release calendar access

    The calendar is disseminated on the INEs Internet website (Publications Calendar)

    
    
  • 8.3User access

    The data are released simultaneously according to the advance release calendar to all interested parties by issuing the press release. At the same time, the data are posted on the INE's Internet website (www.ine.es/en) almost immediately after the press release is issued. Also some predefined tailor-made requests are sent to registered users. Some users could receive partial information under embargo as it is publicly described in the European Statistics Code of Practice

    
    
• 9Frequency of dissemination
  • 9.1Frequency of dissemination

    From 2016 year, the data of the survey is disseminated  biennally.

     

• 10Accessibility and clarity
  • 10.1News release

    The results of the statistical operations are normally disseminated by using press releases that can be accessed via both the corresponding menu and the Press Releases Section in the web

    
    
  • 10.2Publications

    As a general rule, a press release is disseminated, and the results are published in INEbase.

  • 10.3On-line database

    INEbase is the system the INE uses to store statistical information on the Internet. It contains all the information the INE produces in electronic formats. The primary organisation of the information follows the theme-based classification of the Inventory of Statistical Operations of the State General Administration . The basic unit of INEbase is the statistical operation, defined as the set of activities that lead to obtaining statistical results on a determined sector or subject based on the individually collected data. Also included in the scope of this definition are synthesis preparation.

    
    

    All the information of this survey  is  avalaible in INEbase/ Physical area and environment / Environmental statistics/ Water, on the following link:

    https://www.ine.es/dyngs/INEbase/es/operacion.htm?c=Estadistica_C&cid=1254736176834&menu=ultiDatos&idp=1254735976602

  • 10.4Micro-data access
    A lot of statistical operations disseminate public domain anonymized files, available free of charge for downloading in the INE website Microdata Section
    

    The anonymised microdata file can only be provided via specific petition, once the viability of the petition granting access to the information under strict confidentiality conditions is analysed.

  • 10.5Other

    There is no comments.

  • 10.6Documentation on methodology

    A detailed description of the methodology of the surveys may be viewed on the INE website.

    https://www.ine.es/dyngs/INEbase/es/operacion.htm?c=Estadistica_C&cid=1254736176834&menu=metodologia&idp=1254735976602

     
  • 10.7Quality documentation

    This standardized methodological report contains all of the elements of what is considered a "User-oriented quality report" for this operation.

• 11Quality management
  • 11.1Quality assurance

    Quality assurance framework for the INE statistics is based on the ESSCoP, the European Statistics Code of Practice made by EUROSTAT. The ESSCoP is made up of 16 principles, gathered in three areas: Institutional Environment, Processes and Products. Each principle is associated with some indicators which make possible to measure it. In order to evaluate quality, EUROSTAT provides different tools: the indicators mentioned above, Self-assessment based on the DESAP model, peer review, user satisfaction surveys and other proceedings for evaluation.

    
    

    The compilation process of the statistics on water use have established statistical controls and validation rules, for the purpose of detecting and correcting errors and inconsistencies, and carrying out the corresponding corrections and imputations. The controls are based on the establishment of admissible ranges of values, as well as on the crossing of physical variables to identify water flow statuses and destinations, which from a natural environment perspective, cannot occur. The imputations are performed, based on average values previously calculated for the sample data, or elevated from the surveys (irrigation allocations by hectare, water use per employed worker, average prices, etc.)

    On the other hand, during the information collection, measures are introduced to reduce non-response (direct actions from the responsible department toward the respondent units, direct collection from large companies, etc.).

    All of these measures enable obtaining a final statistical product with the required quality and reliability.

  • 11.2Quality assessment

    The sample sizes are sufficient to provide reliable estimates, so much for the national total. In the survey, at the same time as the data collection, the survey framework is updated, for the purpose of identifying those irrigation communities that do not have activity, or that have suspended such activity temporarily.

    On the other hand, and with the objective of evaluating the quality of the final information obtained, this is compared with the external sources available (Ministry of Agriculture, Food and the Environment, sector studies on water use, etc.) ). Likewise, interannual verifications are performed, for the purpose of identifying temporary trends in the data that illustrates the evolution of the statistical phenomenon studied.

     

• 12Relevance
  • 12.1User needs

    The availability of a complete and integrated set of statistical information on water is an essential tool for gaining knowledge on the use of the "water resource", and therefore, for the design and execution of public actions in the hydrographic area.

    The domestic users that are most interested in the surveys on water use in the agrarian sector are the administrative bodies with jurisdiction over the "water resource" (Ministry of Ecological Transition, Autonomous Community Councils), as well as academic researchers.

    On an international scope, the information generated in these surveys serves to meet the international requirements for information (Eurostat, OECD, FAO, United Nations, etc.)

  • 12.2User satisfaction

    The INE has carried out general user satisfaction surveys in 2007, 2010, 2013,  2016 and 2019 and it plans to continue doing so every three years. The purpose of these surveys is to find out what users think about the quality of the information of the INE statistics and the extent to which their needs of information are covered. In addition, additional surveys are carried out in order to acknowledge better other fields such as dissemination of the information, quality of some publications...

    On the INE website, in its section Methods and Projects / Quality and Code of Practice / INE quality management / User surveys are available surveys conducted to date.(Click  next link)

     

    
    

    In the User Satisfaction Surveys conducted to date, it is possible to view the evaluation of the environmental statistics sector in which this statistical operation is centred, which can help direct us with regard to user opinions of it.

  • 12.3Completeness

    The information collected enables meeting all the international information requirements, and in particular, those stipulated by the JQ - Inland Waters questionnaire (Eurostat - OECD).

    R1=100%

• 13Accuracy and reliability
  • 13.1Overall accuracy

    With regard to the survey the sample studied covers the 85% of the total national poulation.. This high degree of sampling coverage enables minimising sampling errors, and together with the aforementioned validation rules, reaches a high degree of accuracy of the survey results.

    I

  • 13.2Sampling error

    With regard to the survey, it is not possible to calculate sampling errors, as the extraction from the sample is not based on probability, because it is based on a population coverage.

     

  • 13.3Non-sampling error

    Non-sampling errors are minimised, decreasing the non-response rate of the respondents via the pertinent repeat interview and re-call processes. As per the information requires that has not been filled in (missing), an imputation process is performed, in which the values of the geographically close irrigation communities are used.

    The non-response rate in the survey  is 7%. (A4=7%)

• 14Timeliness and punctuality
  • 14.1Timeliness

    The data from the survey is disseminated by the INE 18 months following the beginning of the data reference period.

    TP= 18 months

  • 14.2Punctuality

    The dissemination of the data is carried out in accordance with the structural statistics availability calendar that the INE compiles and publishes each year.

    With regard to the surveys on water use in the industry and services sectors, given their pilot and experimental studies nature, there is no availability calendar for the information.

• 15Coherence and Comparability
  • 15.1Comparability - geographical

    In all of the surveys on water use in the economic activity sectors, the availability of a harmonised methodology, a stratified sampling design with proportional allocation criteria, or based on geographical coverage criteria, enables the information to be comparable among the Autonomous Communities.

    A per the international scope, in the completion of the JQ - Inland Waters questionnaires, the methodological recommendations marked in the completion manual are followed, and therefore, the data is comparable at an international level.

  • 15.2Comparability - over time

    In 2006 (time reference of the survey data) a modification of the questionnaire was carried out in order to investigate non-recorded water with its disaggregation into real and apparent losses.

    CC1=14 years

  • 15.3Coherence - cross domain

    Contrasts are performed for the different activity sectors studied, with the results of other surveys carry out by both the INE and other bodies.

  • 15.4Coherence - internal

    Coherence is a fundamental requirement in planning the methodology of the surveys, as in their compilation process. The coherence between the variables is contrasted in all phases of the statistical process. The annual results of the variables are coherent with each other and with the available annual series.

• 16Cost and burden
  • 16.1Cost and burden

    For the purpose of reducing the response burden of respondent units, the completion of the questionnaires is facilitated for large business groups through ,a data collection process, as their particular characteristics are borne in mind. On the other hand, the sample design is coordinated with other surveys, with the objective of decreasing the response burden of respondent units, and the administrative information available is used, so as not to require data unnecessarily.

    Regarding the data collection, online completion by users has been encouraged, as a safe and agile method for respondents,  which has enabled improving the quality levels of the information collected.

    The estimation of the budgetary credit necessary to finance the Water Use Statistics operation, as foreseen in the 2022 Annual Programme, comes to a total of 49,63 thousand euros.

• 17Data revision
  • 17.1Data revision - policy

    The INE of Spain has a policy which regulates the basic aspects of statistical data revision, seeking to ensure process transparency and product quality. This policy is laid out in the document approved by the INE board of directors on 13 March of 2015, which is available on the INE website, in the section "Methods and projects/Quality and Code of Practice/INE’s Quality management/INE’s Revision policy" (link).

    This general policy sets the criteria that the different type of revisions should follow:  routine revision- it is the case of statistics whose production process includes regular revisions-; more extensive revision- when methodological or basic reference source changes take place-; and exceptional revision- for instance, when an error appears in a published statistic-.

    
    

    Preview data is not disseminated, with the data being published when it is final.

  • 17.2Data revision - practice

    Data revisions are not implemented.

• 18Statistical processing
  • 18.1Source data

    The reference framework used is the information from the Central Business Directory (CBD) that the INE compiles and the information compiled in the course of the data collection of the survey.

  • 18.2Frequency of data collection

     For reference year t, the data collection is performed during the September-December period of year t+1.

  • 18.3Data collection

    The information collection is carried out by the postal mailing of the questionnaire, followed by telephone support. Respondents also have the possibility of completing the questionnaire online and mailing it electronically or by fax. Together with the survey questionnaire, the respondent units receive a document with the norms for completing the questionnaire.

    The information collection tasks are complemented, calling, by telephone, those respondents that have not submitted the survey questionnaire duly completed and on time. Support tasks for the collection are also carried out, such as updates to the directory, and the control and revision of the questionnaires.

  • 18.4Data validation

    The management of the sample datafile, both for data collection purposes and for the updating of the framework of respondent units, is carried out via a computer application established to this end, which permits guaranteeing the control and organisation of the entire collection process. This guarantees an efficient control over the process, from the beginning of the data collection onward, since systematic errors when completing the questionnaires can be detected rapidly in the initial stages, which facilitates their correction.

    The initial stage for processing the survey information coincides in time with the actual fieldwork, and is carried out in parallel with the collection, during the entire duration thereof. The main purpose is to establish quality levels that are high enough to enable a correct and adequate recording of the questionnaires, and that significantly simplify the subsequent information processing. The recording of the information that appears in the completed questionnaires is carried out by establishing the control rules necessary for guaranteeing an adequate quality level throughout the process, detecting possible coverage errors and non-response.

  • 18.5Data compilation

    Once the survey file is created, tasks are carried out for the errors and inconsistencies in the identification variables of each record to be detected and filtered; subsequently, different phases of content error filtering and imputation are carried out. Once the different sequential phases of the filtering are complete, the tables are obtained and the analyses performed to detect values outside of the bracket and evident errors, and to compare the results obtained with the available external sources.

  • 18.6Adjustment

    No seasonal adjustments are carried out

• 19Comment
  • 19.1Comment