Rain water harvesting

Rainfall varies throughout the world and per season. For this little problem we are going to explore whether we can use rainwater. We’ll use Scandinavian figures.

GIVEN that rainfall is 500mm per year.


Given a house 25m by 10 meters.

CALCULATE how much rain falls on the roof.

GIVEN that the average person uses 180 litres of water a day.


Would the rainfall on the house above be sufficient to supply a family of four persons all their water needs?

Further work.

Step action pump from New Zeeland

GIVEN that a new kind of pump powered by the force of people stepping on it ( a so-called step action pump) pumps one litre per step.


GIVEN that A fit human can produce 80 steps a minute.


How long would a person need to spend per day pumping water from a rain tank to a roof tank to satisfy their daily needs?


Calculate, for your area if the rainwater falling on your

  • school
  • home
  • or other building you spend time in

is sufficient for your daily needs.

One Response to “Rain water harvesting”
  1. badrithink says:

    Excellent illustrations. Thank you.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: