**2. Literature review**

#### **2.1 Rainwater harvesting system**

In ancient times, rainwater was used to persevere. The use of the rainwater harvesting system has two main aims. The first was to provide water for various household activities, especially drinking, bathing, etc. Secondly, rainwater evaporation from some of the domestic ones impounding systems such as pools and reservoirs made some sort of air-conditioning feeling available which has improved more or less on the microclimate, making it cooler and more comfortable.

Rainwater was the primary source of water supply in old days for drinkable and non-drinkable uses because water supply systems are not yet in development. Simplest method used to make a rainwater harvesting system. No treatment was applied to the collected rainwater before it was used. The systems can be categorized as small, medium and large scale [1]. Normally, the size of rainwater harvesting was based on the size of the catchment area [2].

Rainwater has a lot of potential as the main water resource for the future because of its high quality [3]. Clean rainwater collected not only solved the water crisis problem but also reduce the water treatment cost. For the economic benefit. This system can reduce or cut the utility bill for domestic water. So, RWHS is implemented if the water tariff is higher.
