Toddler hates water. What can I do?

So my 15 month old hatess drinking water, which is why hes constantly constipated.

Ive tried everyy cup you can think of. He drinks a little then throws a tantrum. I literally have to spoon feed him water.. its ridiculous. And even then its a struggle

He’ll drink cucumber water, spoon fed though -.- He can hold the sippy cup and all but doesnt like holding a cup up to drink at all, only a bottle for his milk

Any ideas?