540. HaTov v'HaMeitiv vs. Shehechiyanu

Brachos 10:5

Regarding heavy rains, if a person owns a field by himself, he recite shehechiyanu to thank God; if he owns a field with partners, he recites haTov v’haMeitiv (that God is good and does good). If he doesn’t own a field, he says, “We gratefully acknowledge You, Hashem our God, for every drop that You have caused to descend for us. If our mouths were filled, etc.... All shall thank, praise and bless Your Name, our King. Blessed are You, Hashem, the Almighty Who is deserving of abundant thanks and praise.”

Brachos 10:6

The appropriate bracha on rain is recited when a significant amount of water collects on the surface of the earth, the raindrops cause bubbles to form in the puddles, and the bubbles start to merge into one another.