# What is the right size for a rainwater harvester?

**Sommaire de notre article**

### What is the right size for a rainwater harvester?

1,500 liters The choice of **volume** from **recuperator** of**rainwater** also depends on how you want to use it throughout the year. If you water little (less than 50m²), a **volume** of 1 liter per year is necessary. **For** significant watering (more than 50 m²), your annual needs are between 5 litres.

### How to calculate the amount of rainwater?

As we have just seen, 1 l is equal to 0.001 m³. We can also define that 1 m³ is equal to 1000 litres. So if we base ourselves on the formula for calculating a volume which is: length x width x height and we convert the result, we obtain a volume in liters. How to calculate the amount of rainwater?

### What unit is used to calculate rain?

The unit used is millimeters of precipitation per square meter. Assuming a homogeneous distribution of precipitation on this surface, 1 millimeter of rain represents 1 liter of water per square meter. Is 1 mm of rain a lot?

### How to calculate stormwater flow?

The calculation of stormwater flow is based on the amount of water accumulated as a result of precipitation. Let’s see what water flow means before trying to calculate it.

### How to calculate the water flow?

On an international scale, the dimensioning of the water flow is expressed by the letter Q, generalized notation. Precipitation, capacity of rivers, the unit of measurement is the m3/sec or sometimes the litre/sec. The problem of rainwater drainage