For a more long term solution, (you may already be doing this as you say you eat healthily but just in case!), drink lots of water - surprisingly increased amounts of water decreases water retention as your body has no "need" to retain it as you replensih it and replace it so often, or that's how I was lead to understand it anyway.
Also, you could lower your salt intake as this increases water retention.
Lastly, something I have done myself in the past and noticed a dramatic difference (I guess it depends on how much you drink though) but try cutting out caffeine as this can lead to water retention too.
However I have used Aqua ban in the past and aside from having to pee every 5mins, they were very good at combatting water retention.
Oh, and exercise, that helps too.