Polyuria and polydipsia (exessive peeing and drinking) are never a good sign for mammals. It may be organ trouble, like my Pica, she has amyloidosis which is protein deposits in her kidneys and other organs. The great thing about hamsters is that if there is a problem, like something with the kidneys, they are generally able to live for a long time with reduced kidney function.
I hope it's nothing serious! If you're very concerned I would take her to the vet. I noticed when Pica was young she started with the polyuria/polydipsia and I didn't take her since I assumed it was diabetes and I knew there wasn't much the vet could do for her. But, now that she's been seen it turns out it's a kidney problem and I had her on the wrong diet
I hope all works out for you and your ham!