Various methods have been used for collecting water, but each one by itself has shortcomings that have prevented or limited its application. The method of rainwater collection by using a rainwater harvesting device (rainwater harvesting machine or R.H.M) is a new technique that was inspired by pitcher irrigation, techniques of water harvesting, and drip irrigation. Combination of these three methods had led to the manufacturing of a very simple and practical device that can be used in various parts of the world (including Iran), especially in arid and semi-arid and even in semi-humid regions where access to water is limited or impossible. This device has applications in supplying the water required for agriculture, drinking, tourism, etc. Rainwater harvesting devices  have completely overcome the disadvantages of the three methods mentioned above. It is a simple and multi-purpose tool, and its main application is to provide sufficient water for establishing and developing orchards, planting trees in regions where water is scarce or unavailable, and job creation. Protection of groundwater resources and prevention of erosion are among the most important additional goals in utilizing this device. In the present research, two samples of rainwater harvesting devices with the capacities of storing 430 and 1800 liters of rainwater were first designed, produced, and installed. A rain gauge was then used to measure daily rain and the volume of rainwater stored in the tanks of the devices, and to study their ability to store and save rainwater. Results showed that the devices had the necessary efficiency for harvesting and storing rainwater for when water was needed. The total water loss during the processes of rainwater entrapment and storage until the time it was used amounted to less than five percent.