Two figures in, a clear answer out. The water demand calculator uses population size, mdd to add ratio, phd to add ratio and water requirement per capita to produce average water demand, maximum water demand and peak water demand, applying the standard relationship for this problem in the order the calculation actually needs it.
What Is the Water Demand Calculator?
The water demand calculator works out average water demand, maximum water demand and peak water demand from population size, mdd to add ratio, phd to add ratio and water requirement per capita.
Biological relationships are usually approximations rather than exact laws, so the output is best treated as an estimate with a sensible range around it.
How the Water Demand Calculation Works
The calculation applies the relationship as published, step by step, so each intermediate value can be checked against the underlying theory.
Keep the units consistent throughout. Mixing a percentage with a proportion is the single most common source of an answer that is out by a factor of a hundred.
Assumptions Worth Knowing
Any relationship used here assumes a constant rate, a representative sample, or a stable population. Real populations rarely meet those conditions for long, so treat the answer as a guide.
Where the inputs are field measurements, a single misread value can shift the result noticeably. Measure carefully and record what you used.
A Worked Example
Working through an example, with population size set to 10, mdd to add ratio set to 5, phd to add ratio set to 2, the calculator returns average water demand of 1,100, and maximum water demand of 5,500, and peak water demand of 2,200. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out average water demand?
Enter population size, mdd to add ratio, phd to add ratio and water requirement per capita. The calculator then works through the relationship and reports average water demand, maximum water demand and peak water demand.
What does the water demand actually calculate?
It takes population size, mdd to add ratio, phd to add ratio and water requirement per capita and converts them into average water demand, maximum water demand and peak water demand using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter population size?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Does anything you type get stored?
No. The whole calculation runs inside your browser, and nothing you enter is uploaded, logged or sent anywhere.
Do I have to fill in every field?
Only the fields a particular result depends on. If you leave one blank, the results that need it simply show a note instead of a number, and everything else still works.