How to make a cheap Rain Gauge

Rainfall measurement is very helpful in understanding the weather around you. For example if you want to harvest rainwater, understanding rainfall patterns and quantities helps to get a good design for the storage and recharge. Here is how you can make a cheap rain gauge and start putting it to use this monsoon.

You need a 1 litre or a 2 litre PET or PVC bottle. The bottle should have a flat base and be vertical for the most part.

Cut the bottle at the place it starts to curve and taper. Remove the cap

Using a hot knife helps. Be careful while using it though.

Flip the cut portion and place it like this in the bottle

This will ensure all rain comes in to the bottle and does not evaporate

Take a 6 inch plastic scale and tape it to the bottle from the outside , like so

Fill water in the bottle till the zero mark of the scale. This will give the bottle stability as well as do a ‘zero correction”

This is how your rain gauge will look from the top

Place the rain gauge in a clear place with no trees or any structure to obstruct rainfall. If necessary support it with bricks on the sides to prevent wind from toppling it over.

Take readings everyday at 8.30 a.m. and enter it to a monsoon diary. After the measurement is taken empty the rainwater into a pot and bring the water level to read zero on the scale.

Remember these are approximate measures and it does not matter if the bottle is a 1 litre of a 2 litre or even a 10 litre bottle as long as the bottle is vertical.

At the end of the June- September season on October 1 st add up  all the rainfall measurements that you have taken. How much did it rain in your place?  Was monsoon 2013 good ? What is the average rainfall for your place? Where will you find this information?