Got a very painful joke from my frnd

So 2 days ago i met with my two of my frnds we played football went back to home now with frnds we joke alot about the most shit usually i just let go jokes became very calibrated but this one was very paimful so after playing foot ball we went back to my home they were standing outside i went inside to drink asked them to drink so while one was drinking water my frnd after drinking he gave the bottle to me and i nicely said paani piyega? to my another frnd he said : nahi achut ke ghar ka pani nhi peeta me toh hindu hu and my other frnd started laughing and i was shocked and silenced this guy is been my frnd for more than 7+ years it was way hurtful yesterday i confronted him on whtsapp now i am confused should i take it as a joke or is it just they are using humour to hide thier inner dirt