What if I don’t have a water meter—how do I estimate water consumption?
For many small and medium-sized enterprises (SMEs), water is not tracked directly with a meter. You may work from a shared office, a co-working space, or a rented building where water use is bundled into rent. Yet under the Corporate Sustainability Reporting Directive (CSRD) and the Voluntary Sustainability Reporting Standard for SMEs (VSME), you may be asked to provide water usage data.
The good news: you can estimate your water consumption using simple methods, and this is accepted practice under VSME reporting guidance.
Step 1: Start with utility bills (if available)
Even if you don’t have a separate meter, your landlord or building manager may hold the overall building water bill. This is the best starting point. Once you know the building total, you can work out your business’s share based on:
- Number of employees — divide the building’s total water use by the number of employees working there, then multiply by your own workforce size.
- Floor space — divide by square metres, then multiply by the space you rent.
This provides a fair allocation of water use when you can’t measure it directly.
Step 2: Use employee-based estimates
If no bill is available, you can use average daily water use per employee. A common benchmark is 40–60 litres per employee per day for office settings (covering toilets, handwashing, tea/coffee, cleaning). For more detailed water measurement guidance, see how to measure business water usage.
Formula: Annual water use (litres) = Employees × Average litres per day × Working days per year
Example: A company with 15 employees, working 220 days per year, at 50 litres per person per day: 15 × 50 × 220 = 165,000 litres (165 m³)
Step 3: Estimate based on fixtures and usage
For more accuracy, you can add up water use from fixtures and appliances:
- Toilets — litres per flush × flushes per day × working days
- Taps — litres per minute × estimated use per day × working days
- Dishwasher/kitchen — litres per cycle × cycles per week × weeks per year
This method is helpful if you run a café, workshop, or customer-facing space with heavier water use than a typical office.
Step 4: Note assumptions clearly
CSRD and VSME don’t expect perfection from SMEs — just transparent, reasonable estimates. Always explain how you worked out your numbers, e.g.:
“Water consumption estimated based on 15 employees, 50 litres per person per day, 220 working days.”
This makes your disclosure credible, even if you don’t have precise meter data.
Example disclosure text
In 2024, our company operated from a shared office without a dedicated water meter. Based on employee headcount (15 staff), average use of 50 litres per employee per day, and 220 working days, we estimate our annual water withdrawal at 165 m³. Nearly all water is discharged back into the system, so consumption is considered negligible.
Key Terms
- Corporate Sustainability Reporting Directive (CSRD) — An EU law requiring large companies to report on environmental and social impacts. SMEs are not directly required but may be asked for CSRD-style data.
- Voluntary Sustainability Reporting Standard for SMEs (VSME) — A simplified framework to help SMEs report on sustainability topics, including water.
- Water withdrawal — The total water brought into your business (from mains, wells, etc.).
- Water consumption — Water that is not returned, often through evaporation, irrigation, or embedding in products.
- Estimation methods — Practical approaches (per employee, per square metre, or per fixture) used when direct meter data is unavailable.
- SME (Small and Medium-sized Enterprise) — A business with fewer than 250 employees, turnover under €50m, or balance sheet under €25m.