Water Demand Calculator
Estimate daily demand, peak demand, diversity effect, and storage requirement.
Open ToolWater Tank Capacity Planner
A water tank sizing planner for daily demand, reserve days, usable tank volume, fire reserve, and refill planning. Includes formulas, sample data, warnings, related tools, and a downloadable MEP report.
What is a water tank capacity calculator?
A water tank capacity calculator estimates the storage volume needed for a building based on daily water demand, reserve duration, usable tank percentage, fire reserve, and refill assumptions. MEP engineers, plumbers, consultants, and facility teams use it during early design to check whether a proposed tank size is practical before detailed authority review. The calculator is useful for apartments, villas, offices, schools, warehouses, commercial buildings, and mixed-use projects. It separates domestic storage from fire reserve where that distinction is required, then converts the planning demand into a gross tank volume. The result is not a final authority-approved tank design because local plumbing codes, civil defense requirements, utility supply reliability, water quality, compartmentation, access, overflow, maintenance clearance, and project specifications still control the final size. Use it as a fast planning check before detailed design.
Inputs
Forms are empty on load. Use sample data to preview the workflow or enter your own project values.
Learn more
Formula logic, use cases, assumptions, and limits for this tool.
How this tool helps
Use this to plan tank volume and refill rate. Keep fire reserve and domestic storage logic clearly separated where required.
Assumptions and limits
This tool provides a planning-level result. It does not replace detailed engineering design, approved software, manufacturer data, authority requirements, or project specifications.
Typical use cases
- Early estimation and tender support.
- BOQ sanity checking and technical review.
- Site discussion before final engineering verification.
- Comparison of alternatives using consistent assumptions.
Result interpretation
Read the recommendation, warning, and confidence sections together. A result without warnings is still not an approval; it only means the entered values did not trigger built-in planning alerts.
Input definitions and typical values
These notes explain what each input means and which values usually produce a more reliable planning result.
Code / standard profile
Selects the planning profile used for conservative defaults. Use the project authority or client standard where known; otherwise use the closest regional profile. Options: GCC project planning, IPC planning.
Daily domestic demand m3/day
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Reserve period days
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Separate fire reserve m3
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Usable tank volume %
Percentage of tank volume that is usable after freeboard, dead storage, suction level, and practical operating limits.
Required refill time hours
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Practical verification checklist
- Confirm the selected standard profile is suitable for the project location and authority.
- Replace sample values with project drawings, schedules, equipment data, or measured site values.
- Review warnings, methodology, and PDF report before using the result outside early planning.
- Verify final decisions against official standards, manufacturer data, consultant specifications, and local approvals.
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Open ToolCalculation methodology
Domestic reserve plus fire reserve is divided by usable storage percentage; refill rate is derived from gross volume and refill hours.
Inputs are treated as planning assumptions. The calculator shows warnings when entered values fall outside practical thresholds or selected standard-profile limits.
Version history
- v1.3.6-prelaunch: Added methodology, standard profile support, version notes, and direct PDF report download.
- v1.3.5: Calculator page added with sample data, warnings, and print-ready report layout.
Stage 2 roadmap: optional saved projects, dashboards, and shared calculation history without forcing login for free use.
Trust and verification
Every result includes assumptions, warning logic, and a downloadable report. Final engineering decisions still need qualified review, local authority approval, manufacturer data, and project specifications.
Worked example
Use the sample data button to load a realistic scenario, then download the PDF report to review inputs, results, methodology, warnings, and disclaimers in one place.