--- title: Daily Water Requirement Calculator for Housing Societies description: Estimate daily water demand for 100, 500 or 1,000 flats using occupancy and litres per person. Include common-area uses, measured data and a clear uncertainty range. --- [Skip to content](https://www.towneve.com/resources/daily-water-requirement-calculator#main) [![TownEve](https://www.towneve.com/hs-fs/hubfs/raw_assets/public/Towneve-Theme/assets/logo.png?width=164&height=70&name=logo.png)](https://www.towneve.com/) Menu - [Water Management](https://www.towneve.com/water-management) ⌄ - [How It Works](https://www.towneve.com/resources/how-it-works) - Solutions ⌄ - [For Builders](https://www.towneve.com/resources/builder-water-monitoring) - [Resources](https://www.towneve.com/resources) ⌄ - [Case Studies](https://www.towneve.com/resources/tag/case-studies) - [About](https://www.towneve.com/about) - [Contact](https://www.towneve.com/contact) [Log in](https://water.towneve.com)[Request an Assessment](https://www.towneve.com/contact/) 1. [Home](https://www.towneve.com/) 2. [Resources](https://www.towneve.com/resources) 3. Daily Water Requirement Calculator for Housing Societies [Guides](https://www.towneve.com/resources/tag/guides) # Daily Water Requirement Calculator for Housing Societies TownEve Editorial Team · October 1, 2026 ## QUICK ANSWER Daily residential water demand can be estimated by multiplying the number of occupied flats by the average residents per occupied flat and the assumed litres used per person per day. Treat this as one planning input to the broader [housing society water budget](https://www.towneve.com/resources/housing-society-water-budgeting), not as a measured consumption result. Residential demand (litres/day) = occupied flats × residents per occupied flat × assumed litres/person/day. For a more complete society budget, add separately estimated or measured common-area uses, account for the different water services and check whether the result matches actual supply and meter records. This calculator estimates demand; it does not directly measure water delivered or consumed. ## CALCULATOR: INPUTS AND OUTPUTS ## Inputs: 1\. Total flats: whole number, at least zero. 2\. Occupancy rate: percentage from 0 to 100. Prefer an actual occupied-flat count where available. 3\. Average residents per occupied flat: nonnegative number; source and date should be recorded. 4\. Assumed daily litres per person (LPCD): user-selected planning assumption, not a universal entitlement or mandatory consumption level. 5\. Separately measured or estimated daily common-area demand (litres): optional; use zero only when genuinely absent, not when unknown. 6\. Other separately measured or estimated demand (litres): optional; define service and prevent double counting. 7\. Scenario labels: baseline, low-demand and high-demand assumptions, if reliable data is not available. ## Outputs: Estimated occupied flats = total flats × occupancy rate / 100. Estimated residents = estimated occupied flats × residents per occupied flat. Estimated residential demand (litres/day) = estimated residents × LPCD. Estimated total demand (litres/day) = estimated residential demand + separately counted common-area demand + other non-overlapping demand. Estimated total demand (kilolitres/day) = estimated total demand (litres/day) / 1,000. Record the input assumptions alongside the result and compare a range of plausible demand scenarios. The result remains a planning estimate until supported by appropriate measurement. ## WORKED EXAMPLES — ASSUMPTIONS, NOT SITE MEASUREMENTS Example A: 100 flats, 90% occupied, 3 residents per occupied flat, 100 LPCD. Occupied flats = 90. Estimated residents = 270. Residential demand = 27,000 L/day = 27 kL/day, before separately accounted common-area demand. Example B: 500 flats, 100% occupied, 3 residents per occupied flat, 135 LPCD. Estimated residents = 1,500. Residential demand = 202,500 L/day = 202.5 kL/day, before separately accounted common-area demand. Example C: 1,000 flats, 80% occupied, 3.5 residents per occupied flat, 135 LPCD. Estimated occupied flats = 800. Estimated residents = 2,800. Residential demand = 378,000 L/day = 378 kL/day, before separately accounted common-area demand. The LPCD figures here are illustrative scenario inputs. They are not a claim that every Indian resident uses 100 or 135 litres per day. Local design standards, service categories, actual metering and current directions must be checked for the specific purpose. ## A 500-FLAT SOCIETY: WHY ONE NUMBER IS NOT ENOUGH Take 500 flats, all occupied, with three residents each. At 100 LPCD, the residential estimate is 150 kL/day. At 135 LPCD, it is 202.5 kL/day. At 150 LPCD, it is 225 kL/day. The difference between the first and third scenarios is 75 kL/day. That is why the assumed per-person rate must be visible rather than buried inside a calculator. Actual occupancy matters too. If only 80% of the 500 flats are occupied and the same three-resident and 135-LPCD assumptions are retained, estimated residential demand is 162 kL/day. For an operating society, replace assumptions with reliable measured records wherever possible. WHAT BELONGS IN THE WATER BUDGET? Separate the water services before adding quantities. Domestic and drinking-water use may be supplied and metered differently. Gardening, cleaning, clubhouse use and other common-area requirements may need separate entries. Treated recycled water may serve particular permitted uses and should not be casually added to a potable-water requirement. Record the water service, the quantity, the accounting period, whether it is measured or estimated, and the source. If a common-area volume is already included in a bulk-meter reading, do not add it again. Do not count internal transfers from an underground tank to an overhead tank as new water supplied to the society. ## ESTIMATE VERSUS MEASUREMENT The occupancy × LPCD method is a planning estimate. A verified incoming bulk meter records water entering a defined boundary. A verified outgoing meter records water passing a defined point. Tank-level data records changes in stored volume. These are different observations. A tank can fill and drain simultaneously; its level change is the net effect and cannot independently separate unknown inflow and outflow. ## For a defined boundary and time period: Change in stored water = external inflow − external outflow, with documented adjustments where required. Where the accounting boundary includes both underground and overhead tanks, pumping between them is an internal transfer. Where the boundary is one tank, that transfer is an inflow or outflow for that tank. A difference between the estimate and observed records is a reason to examine assumptions and measurements, not automatic proof of leakage. ## HOW TO USE THE ESTIMATE FOR STORAGE PLANNING Suppose a society estimates 200 kL/day for a particular water service. A no-replenishment illustration for 300 kL of verified usable water is: 300 kL ÷ 200 kL/day = 1.5 days. That arithmetic is conditional on the assumed demand remaining constant, all 300 kL being usable and deliverable, and no replenishment. It is not a guarantee of uninterrupted tap supply. The usable-water quantity must exclude inaccessible dead storage. For TownEve-monitored tanks, setup defines tank-specific 0% and 100% reference levels against the configured geometry, so unusable or dead-water portions can be excluded from usable-water calculations. These settings are maintained in software and can be changed when the verified tank configuration changes. For a full supply-risk estimate, account for replenishment timing, tank separation, transfer availability, changing demand and a separately chosen operational reserve. A separate runway calculation can show how those supply and demand scenarios affect the time to a chosen reserve. ## HOW TO IMPROVE ACCURACY OVER TIME Begin with an inventory of water services and tanks. Verify occupancy and the assumptions behind any per-person rate. Record actual municipal, borewell and tanker inflows with their measurement status. Compare successive periods on a consistent boundary. Check meter readings, timestamps and known operational events before interpreting a discrepancy. Where instrumentation is available, use measured volumes. Where it is not, retain an explicit estimate and confidence note rather than replacing “unknown” with zero. A useful committee report displays the estimate and its assumptions next to observed supply and usable storage. It should not conflate them. ## WHERE TOWNEVE FITS TownEve currently monitors overhead and underground tanks with contactless ultrasonic sensors, provides current and historical tank-level visibility, configured email alerts and telemetry-freshness monitoring, and derives tank-specific level and stored volume from measured depth and configured tank geometry. Tank-specific 0% and 100% reference levels define the usable range in software. These capabilities strengthen the storage side of a water budget. They do not turn an occupancy-based estimate into measured consumption or directly measure all incoming water. Direct pump-state monitoring and remote pump operation are in development and testing; tanker workflows are in development. Flow-meter integration is supported by the app but flow-meter hardware has not yet been deployed. Separately, manually controlled no-inflow and valve-isolation observations have already been tested for withdrawal and consumption analysis under suitable operating boundaries. Use TownEve as part of an auditable water-management process, not as a substitute for verifying the property's water system. ## FREQUENTLY ASKED QUESTIONS How much water does a 500-flat society need daily? There is no single reliable number without occupancy and service assumptions. At 500 occupied flats, three residents per flat and an illustrative 135 LPCD, estimated residential demand is 202.5 kL/day, excluding separately counted uses. How much water does a 1,000-flat society need? At 80% occupancy, 3.5 residents per occupied flat and an illustrative 135 LPCD, the residential estimate is 378 kL/day. Different assumptions produce different results. What does LPCD mean? Litres per capita per day: an average daily quantity per person. State whether it is a planning assumption, a design benchmark or a measured average. Should tanker volume be included in daily demand? No. Tanker deliveries are a supply source. Compare verified supply against demand and storage change; do not add supply to the demand side. Can I estimate consumption from tank levels alone? Tank-level changes reveal net storage changes. Simultaneous unknown inflow and outflow cannot be separated from level alone. Does the calculation include dead storage? The demand estimate does not calculate storage. When comparing demand with tank reserves, use verified usable water and exclude configured inaccessible volume. Should recycled water be added to drinking-water demand? Keep water services distinct and account for actual permitted uses and the site's plumbing. Do not add a recycled-water volume to a potable-water requirement without a legitimate accounting reason. Can this estimate forecast the date a society runs out? Only as a conditional scenario once usable storage, replenishment, withdrawal assumptions and operational constraints are supplied. An occupancy estimate alone cannot forecast a shortage. Explore further ## Understand your water system. Plan the next step. Browse more practical resources or discuss your property's monitoring needs. [Request a Water Monitoring Assessment](https://www.towneve.com/contact/)[All resources →](https://www.towneve.com/resources) TownEve · CyberGrove Solutions Private Limited Water monitoring for residential communities. 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