Water Demand Calculator
Estimate daily demand, peak demand, diversity effect, and storage requirement.
Open ToolDrainage Pipe Sizing Assistant
A drainage planning assistant that estimates fixture-unit load and compares it against selected pipe diameter and slope.
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 as a planning assistant only. Drainage design is code-sensitive and must be checked against local authority tables and approved standards.
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.
Water closets qty
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Wash basins qty
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Sinks qty
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Floor drains qty
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Selected pipe diameter mm
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Pipe slope %
Percentage adjustment used for diversity, derating, margin, reserve, or contingency. Use project-specific assumptions 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.
Related tools
Other tools in Plumbing & Drainage.
Pump Head Calculator
Calculate static head, pressure head, friction loss, velocity, and total dynamic head.
Open Tool
Water Tank Capacity Planner
Calculate domestic tank volume, fire reserve separation, usable volume, and refill rate.
Open Tool
Hot Water Demand Calculator
Estimate hot water storage, heating energy, recovery rate, and heater capacity.
Open ToolCalculation methodology
Fixture unit load is converted to a planning pipe diameter and checked against selected diameter and slope.
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.