How Much Water Does Your Society Actually Use?

“We ordered three tankers yesterday.”

“The overhead tank emptied earlier than usual.”

“Our water bill has gone up.”

These observations can signal a problem, but they do not answer the same question. Tanker purchases describe one source of supply. A tank level describes stored water. A bill describes a charge, sometimes alongside a reading for a longer period.

To understand water use, your society needs a consistent record of what is measured, where it is measured and what changed during that period.

You can begin with the records and equipment already available. Start simple, and label estimates honestly.

1. Decide what you want to measure

Begin with one question:

Are we tracking incoming water, water leaving storage, or water used across the society?

These quantities are related, but they are not interchangeable.

• Incoming supply: Water entering from municipal supply, tankers, borewells or other sources.
• Water leaving storage: Water passing through a measured outlet or distribution line.
• Society water use: Water going to homes and common activities, including losses within the chosen measurement boundary.

Draw a simple map of your water system with the maintenance team. Mark each source, tank, meter and main distribution route. If there are separate drinking-water and treated-water systems, record them separately.

This prevents a common mistake: counting the same water once as incoming supply and again when a pump transfers it to an overhead tank.

Start here: Write a label above your log, such as “Municipal inlet meter” or “Metered supply to residential blocks.”

2. Use meter readings consistently

Where a working cumulative meter is available, take a reading at the same time each day. Note the meter identity, units and date, and take a photograph where practical.

Period volume = closing reading − opening reading

For example:

One kilolitre (kL) equals 1,000 litres.

What does that 42,000 litres mean? It depends on the meter's location. At a municipal inlet, it is measured municipal inflow. At a distribution outlet, it is the volume passing through that outlet. It is not automatically total household consumption.

Check that the meter covers the intended line and is functioning. Record resets, replacements, suspected faults and missing readings rather than inventing a value to fill the gap.

3. Record tanker deliveries as volumes, not just counts

“Two tankers” is not enough information if vehicles or deliveries have different capacities.

For each delivery, record:

• Date and time.
• Supplier or vehicle identifier.
• Quantity on the delivery record, with units.
• Any independently measured quantity, if available.
• Receiving tank and any problem noticed during unloading.

Keep the delivery slip or invoice. If you have only the supplier's stated quantity, label it reported delivery volume, not verified measurement.

For illustration, two deliveries each reported as 10,000 litres total 20,000 litres of reported supply. That does not establish how much residents used that day.

4. Account for changes in tank storage

A society may receive a large delivery today and use some of that water tomorrow. Equally, a day with little incoming supply may be supported by water already stored.

For a boundary around your society's storage and distribution system:

Water used or lost during the period ≈ total inflow + opening storage − closing storage

This assumes the relevant sources and storage are included and any other transfers across the boundary are accounted for.

Consider an illustrative day:

50,000 + 30,000 − 35,000 = 45,000 litres

That figure includes uses and losses inside the boundary. It does not tell you how much went to drinking, bathing, cleaning or leakage.

Tank-level estimates can be imprecise. Use a verified level-to-volume relationship or an appropriate measurement system; do not assume half the height always means half the volume. Never enter a tank or climb to an unsafe position to take a reading.

If storage cannot be estimated reliably, keep reporting incoming supply and describe the limitation. A clearly labelled supply record is more useful than a falsely precise consumption figure.

5. Keep one daily log

Start with a format your team can maintain.

Assign one person to maintain the record and a backup for leave or shift changes. Keep the source documents alongside it.

Do not add multiple meters together until you know they measure separate flows. A main meter and its downstream block meters may describe overlapping volumes.

6. Build a baseline before judging progress

Collect a consistent record over several weeks where practical. Include enough days to see ordinary variation rather than treating one unusually high or low day as normal.

Note factors that can affect comparisons:

• Occupied flats and approximate resident numbers.
• Guests, events or unusual cleaning activity.
• Supply interruptions and changes in storage.
• Tanker deliveries or unmeasured sources.
• Repairs, overflows and meter faults.

Compare similar periods using the same measurement boundary and method. Lower recorded inflow during a supply cut is not, by itself, evidence of reduced demand or successful conservation.

Useful first question: “Are these two periods genuinely comparable?”

7. Turn a target into a calculation

Once you have a credible baseline, a saving target becomes easier to discuss.

For illustration, if comparable measured or estimated usage averages 60,000 litres a day, a 10% reduction would mean 6,000 litres less, bringing the target to 54,000 litres a day.

Reduction percentage = (baseline usage − comparison usage) ÷ baseline usage × 100

Use like-for-like figures and a non-zero baseline. If the starting figure represents incoming supply, report a change in incoming supply rather than calling it a verified consumption saving.

Protect essential drinking, cooking, sanitation and hygiene needs. A target should guide investigation and practical improvements, not become an arbitrary household restriction.

8. Investigate changes without jumping to conclusions

A sudden increase can be a reason to inspect, not proof of a leak.

First check the readings, units and records. Then review changes in storage, occupancy, supply and activities. If the increase remains unexplained, ask the maintenance team to inspect relevant tanks, valves, toilets and accessible pipes.

Likewise, lower tanker purchases may reflect better municipal supply rather than lower total use.

Report what the evidence supports:

• “Reported tanker purchases fell this month.”
• “Measured distribution volume fell across comparable weeks.”
• “Total use remains uncertain because one source is unmetered.”

That clarity makes committee decisions more useful and resident communication more trustworthy.

Share progress, not blame

Share a short society-level update: the period covered, what was measured, the result and any limitations. Include actions completed, such as an overflow repaired or a faulty meter checked.

Avoid naming or blaming households based on society-level figures. Those readings cannot identify an individual flat's consumption.

Sharing is caring — and a clear water log gives the conversation something better than guesswork. Share this guide with your committee or neighbouring societies so they can begin their own record too.

Your first-week checklist

• Map the sources, tanks and meters with the maintenance team.
• Decide the measurement boundary and label the log.
• Confirm units and choose a consistent reading time.
• Assign a responsible person and backup.
• Keep tanker quantities and their measurement basis.
• Record storage changes where reliable information is available.
• Note unusual events and missing data.
• Review the first week's records before making claims.

Begin with one honest record

You do not need a perfect dashboard to start. You need a clear question, a consistent method and a record someone will maintain.

This week, ask: “What do we actually measure — and what are we still estimating?”

The answer will show your society where to begin improving both its information and its water management.

Share this article with your society committee, manager and maintenance team.

← Previous: Tank Overflows — A Society Problem You Can Start Fixing Today
Coming next in this series: “Less Water, Better Planning: A Checklist for Society Committees.”