Andrew Tate Says He's 'Forced To Drink Poisoned Water' in Miami Jail

9 AM PT -- The Federal Bureau of Prisons has responded to Tate's gripes, telling TMZ ... "FDC Miami receives an annual water certification from Miami-Dade Water and Sewer concerning the quality of the drinking water supply. Currently, the drinking water at FDC Miami is certified safe to drink."

Andrew Tate claims his conditions in jail are cruel and unusual ... because the drinking water is not up to his standards ... and it's giving him a tummy ache.

The influencer went on a social media rant over the weekend, claiming the only water he has in his cell comes from a "brown and filthy" shower faucet.

Andrew says he is not allowed to drink bottled water and is being "forced to drink poisoned water." He says the water is not clean and is giving him "persistent stomach problems." Sorry, no Evian or Fiji water in the clink.

We broke the story ... Andrew and his brother Tristan Tate were arrested earlier this month in Miami after U.S. Marshals executed a United Kingdom extradition warrant seeking to return them across the pond on charges of rape, sex trafficking and child pornography.

Andrew says his rights are being trampled on ... but he's not getting much support over his H₂O gripes in the comments -- most are dunking on him and antagonizing him with comments like, "Not good bro, remember to leave a bad review on tripadvisor or something..."

He also says he's being held in the Special Housing Unit ... with no commissary, no phone calls and no yard time.

Tate brothers lawyer Joseph McBride tells TMZ ... there's a hearing today where he'll "exhaust all appropriate measures at this time to ensure that Andrew and Tristan are well taken care of."

McBride says several issues will be addressed with the judge, because ... "We are gravely concerned about Andrew and Tristan's physical, spiritual and psychological health in solitary confinement."