Assessing Water Savings and Cost-Effectiveness of Non-Potable Water Systems in Brazilian Residential Buildings

Assessing Water Savings and Cost-Effectiveness of Non-Potable Water Systems in Brazilian Residential Buildings | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Assessing Water Savings and Cost-Effectiveness of Non-Potable Water Systems in Brazilian Residential Buildings Daniel Sant'Ana, Livia Santana This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8348808/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study evaluates the potential for reducing residential potable water consumption in the Federal District, Brazil, through the adoption of rainwater harvesting systems (RWHS) and greywater reuse systems (GWRS). The integrated analysis combined hydraulic and economic simulations, considering saturation volumes, economically feasible limits, levelized cost of water (AIC), and payback periods across four representative residential typologies. The results show that the feasibility of these solutions varies significantly across income groups and system types. RWHS proved economically viable only in high-income households, where larger roof areas allowed for optimal storage volumes of 20 m³ in scenarios including irrigation and floor washing, with or without toilet flushing, and 50 m³ in scenarios that also included laundry use. In these cases, AIC values remained positive (0.14–0.78 US $ /m³), although payback periods were long (16–18 years). In the remaining typologies, low annual savings combined with installation costs made the system unfeasible. GWRS showed broader applicability. In high-income households, simple solutions such as bucket-based systems or subsurface diversion for irrigation outperformed RWHS, presenting very short payback periods (0.1–2.1 years) and positive AIC values (2.13–3.22 US $ /m³). In upper-middle-income households, treated greywater systems were the most advantageous due to higher greywater generation and the dilution of fixed costs across multiple housing units (AIC of 1.43–1.57 US $ /m³; payback of 1.2–2.1 years). In lower-middle- and low-income typologies, only low-complexity solutions proved economically viable. Civil Engineering Environmental Engineering Environmental Economics City Management and Urban Policy Economic feasibility Greywater reuse Non-potable water systems Rainwater harvesting Residential water consumption Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8348808","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":559590786,"identity":"4204f510-396c-466f-8e6a-08cc18a9e064","order_by":0,"name":"Daniel 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Buildings\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Brasília","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Economic feasibility, Greywater reuse, Non-potable water systems, Rainwater harvesting, Residential water consumption","lastPublishedDoi":"10.21203/rs.3.rs-8348808/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8348808/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study evaluates the potential for reducing residential potable water consumption in the Federal District, Brazil, through the adoption of rainwater harvesting systems (RWHS) and greywater reuse systems (GWRS). The integrated analysis combined hydraulic and economic simulations, considering saturation volumes, economically feasible limits, levelized cost of water (AIC), and payback periods across four representative residential typologies. The results show that the feasibility of these solutions varies significantly across income groups and system types. RWHS proved economically viable only in high-income households, where larger roof areas allowed for optimal storage volumes of 20 m\u0026sup3; in scenarios including irrigation and floor washing, with or without toilet flushing, and 50 m\u0026sup3; in scenarios that also included laundry use. In these cases, AIC values remained positive (0.14\u0026ndash;0.78 US\u003cspan\u003e$\u003c/span\u003e/m\u0026sup3;), although payback periods were long (16\u0026ndash;18 years). In the remaining typologies, low annual savings combined with installation costs made the system unfeasible. GWRS showed broader applicability. In high-income households, simple solutions such as bucket-based systems or subsurface diversion for irrigation outperformed RWHS, presenting very short payback periods (0.1\u0026ndash;2.1 years) and positive AIC values (2.13\u0026ndash;3.22 US\u003cspan\u003e$\u003c/span\u003e/m\u0026sup3;). In upper-middle-income households, treated greywater systems were the most advantageous due to higher greywater generation and the dilution of fixed costs across multiple housing units (AIC of 1.43\u0026ndash;1.57 US\u003cspan\u003e$\u003c/span\u003e/m\u0026sup3;; payback of 1.2\u0026ndash;2.1 years). In lower-middle- and low-income typologies, only low-complexity solutions proved economically viable.\u003c/p\u003e","manuscriptTitle":"Assessing Water Savings and Cost-Effectiveness of Non-Potable Water Systems in Brazilian Residential Buildings","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-16 15:22:28","doi":"10.21203/rs.3.rs-8348808/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b63638fc-1ea5-445d-a8bd-08ea5454ab48","owner":[],"postedDate":"December 16th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":59578393,"name":"Civil Engineering"},{"id":59578394,"name":"Environmental Engineering"},{"id":59578395,"name":"Environmental Economics"},{"id":59578396,"name":"City Management and Urban Policy"}],"tags":[],"updatedAt":"2025-12-16T15:22:28+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-16 15:22:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8348808","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8348808","identity":"rs-8348808","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}