Hello there! Welcome to our community
"Duck's only need enough water to dunk their heads" is a saying that is quite frequently repeated around here, and is, IMO, plain nonsense. Take it this way, I could go without showering for a few months, and would I live (?) YES, but I'd likely look comparable to a Neanderthal. The same thing can be applied to ducks, but with a lot greater emphasis, there is a reason they are called WATERfowl, to stay healthy these birds need to have an adequate, and deep amount of supply of water, or you’re bound to have problems like wet feather, sticky eye, ectoparasites, among other problems.
Of course, when It comes to providing a deep water source in winter time, for the most of us, that’s not really feasible, so just a bucket will suffice, you’ll notice towards the end they’ll start looking rattier, but will regain appropriate feather condition once a deep water source is once available.
I have two creeks, and man-made one pond that run through my property, so the duck/geese tend to use those the most, but I do have a little pre-formed pond sunken into the ground near the house that the Call’s frequently use. I placed the pond in shade, as to decrease algae growth, and use a pump to circulate oxygen into the water to decrease anaerobic bacterial growth. Once a week, I set a large sump pump into the pond and pump it out over the yard.