Hi Mr. Hasbi let me try to give feedback on your writing.
The diagram illustrates the ways to 1. In your sentence, after "to", it must be V1.
reused (reuse) rainwater. Overall, it can be seen that there are three treatments to purifying (purify) water these are dam water, wastewater and storm water. Predominantly of water is used to household purposes.
To begin with, rain water from the sky is collected in dam. After this, water is flowed to water treatment plant for filtering. Then, water already
to (can) be used for daily activity (need) like for drinking water. For rainwater which fall on house's roof is particular drip cup is accommodated before water sent into home.
Before waste(d) water from house recycled and reused again, it has to pass through 1. "Water" is a noun and before noun, it must be an adjective for explaining the noun.2. The word "efflorescent" is an adjective and after "to", it must be followed by adjective + noun.
wastewater (wasted water) treatment. In this step, liquid waste (wasted liquid) is treated the excess of water and then channel it to the lake. After that, result of the isolation leave water for purifying again and it is used again for household needs. Storm water treatment is a drainage canal to efflorescent to the river.