Is the word d'água the same in Brazilian and European Portuguese?

Yes

The word "d'água" (a contraction of the preposition de and the noun água) is identical in both Brazilian and Continental Portuguese regarding its meaning, grammar, and spelling. The only difference is pronunciation. In Brazilian Portuguese, the vowels are typically pronounced more openly and clearly. In Continental Portuguese, there is a much stronger tendency toward vowel reduction and elision, meaning the "e" in the contraction is often almost entirely swallowed, making the transition between the "d" and "água" much more compressed and fluid.

Brazilian Portuguese Examples

1. "Caiu uma chuva d'água que molhou todo o cachorro." (A downpour fell that wet the whole dog.)
2. "A corrente d'água está muito forte hoje." (The water current is very strong today.)
3. "A queda d'água é o ponto turístico da região." (The waterfall is the region's tourist attraction.)
4. "A força d'água moveu as pedras do caminho." (The force of the water moved the stones from the path.)
5. "O menino estava com a boca cheia d'água." (The boy had his mouth full of water.)

Continental Portuguese Examples

1. "Caiu uma chuva d'água que molhou todo o cão." (A downpour fell that wet the whole dog.)
2. "A corrente d'água está muito forte hoje." (The water current is very strong today.)
3. "A queda d'água é o ponto turístico da região." (The waterfall is the region's tourist attraction.)
4. "A força d'água moveu as pedras do caminho." (The force of the water moved the stones from the path.)
5. "O rapaz estava com a boca cheia d'água." (The boy had his mouth full of water.)