Source? There are many sources that show that pH in urine and saliva increases when people drink alkaline water.

Of course urine would, its the result of kidneys eliminating the acid brought to them by the plasma buffer system. But blood and body Ph don't change.

The body is incredibly complex so I'm not saying this is conclusive but here's a source plus a lot of explanation with numerous experiments.

https://pmc.ncbi.nlm.nih.gov/articles/PMC3828631/

Another thing: Calcium strongly associates with acid.

And there's no evidence of osteoporosis or bone leaching with high acid diets.