Rainwater & Greywater Harvesting Calculator

About Water Harvesting

WATER HARVESTING CALCULATOR

For any water harvesting plan, a careful assessment should be made of the sources and needs for harvested waters. The following calculator can provide a rough assessment of these numbers for your project.

All fields are required. Enter numbers only - no commas. Enter 0's if data is not relevant.

What will you see? If you would like to see a sample of the output from the Calculator that can also help you interpret the results, click here.

On average, how many people will occupy your building on any given day?
On average, how many days per week will your building be occupied by the majority of people? (think “normal work week” – 5 or 6, or residential use - 7)
On average, how many hours per day will the building be occupied by these people (think “normal work week” 8-10, or residential use - 24)
Will the building have extra-high efficiency toilets and urinals (1 gallon flush or less)? Answer “Yes” or “No”
For the next 3 questions, visit Weatherbase and enter the zip code for your building to determine average rainfall quantities in your area.
What is the average annual total number of inches of rain in your area?
Look at the monthly averages for rainfall. What is the average rainfall during the lowest month?
Look at the monthly averages for rainfall. What is the average rainfall during the highest month?
Enter the approximate dimensions of the building’s rooftop accessible to rainfall:
Roof length (in feet)
Roof Width (in feet)
Enter the approximate dimensions of the parking area accessible to rainfall:
Parking area length (in feet)
Parking Area Width (in feet)

Wahaso can provide a preliminary monthly analysis & report for your building and area at no charge. Contact Us if you are interested.