How long have you noticed this? Budgies usually have pretty dry droppings. They can get a little watery if the budgie is eating lots of greens, veggies or other juicy foods. The only time I've noticed droppings of 'just water' in my own budgie is right after a bath when he's preening himself. He seems to swallow a lot of water in the process. But it doesn't last long.
If you have been noticing the watery droppings more than a day or so, I think a vet visit would be best. Budgies can be prone to diabetes and some kidney problems which could cause watery droppings.

Karen
Chico (conure) and Pippin (budgie)
WI

Thank you so much for writing. It is highly appreciated. Ollie has not eaten any greens or juicy stuff. His droppings have now gone to a dark green colour and runny in consistency (i gave him some tea (withoug milk etc) last night and he munched on some toast crumbs) Do you still think a trip to the vet is in order?

Runny droppings is not good either. I would watch him closely, make sure he is acting ok and is eating enough (sick birds may pick through their dishes but not actually eat as much as normal). Unusual droppings that persist even when a bird has not eaten anything unusual are often a sign of illness. If you don't have a regular vet, I'd suggest at least finding one to be ready. Budgies are so tiny, you really need to find a good avian vet. It usually isn't worthwhile to take a budgie to a vet without a lot of bird experience.

Karen
Chico (conure) and Pippin (budgie)
WI