Learn Dutch: De straat overstroomt doordat het hard regent. - The street floods because it rains hard.

Doordat expresses a strict, objective cause-and-effect relationship. It means 'due to the fact that' or 'caused by'. There is no human intention involved—the rain physically causes the flood. Omdat is generally used for reasons or motivations (like 'I stay inside because it rains'). Note that in casual, everyday Dutch, many people just use omdat for both!

Why is the verb regent at the very end of the sentence?

Doordat is a subordinating conjunction, meaning it introduces a dependent clause. In Dutch, these conjunctions push the conjugated verb to the end of their clause. That is why the word order is doordat het hard regent (literally: 'because it hard rains') instead of doordat het regent hard.

Is overstroomt a separable verb?

In this context, no. The verb overstromen is tricky because it has two forms. When it means 'to flood' (like a street or a country), it is inseparable. When it means a container physically overflows (like a bucket), it is separable and becomes stroomt over. Here, the street is flooding, so the verb stays together as one word.

In English we say it is raining 'heavily'. Why does the Dutch sentence use hard?

In Dutch, the most natural way to describe intense rain is with the adverb hard (hard or fast). You wouldn't use zwaar (heavy) to describe rain in Dutch, even though that is the direct translation of the English phrase.