It depends. If the water is really white then yes, that will get you in the ballpark. But if the water is white in the photographs only because all three color channels are completely at max value you won't have much success.
You can actually create a WB correction after the fact assuming you still have the filter in question. Under similar lighting (including any tree cover or anything else that influences color) take some properly exposed shots of a gray card. Then put the filter on, use the same strength setting as you used for the original photos, and take a properly exposed shot of the gray card.
Import the raw files into your raw converter of choice, use the color temperature adjustment to get the unfiltered gray card shot properly balanced (you'll know it when the [R,G,B] values are all the same, like [115,115,115]). Next, apply the same color temperature setting to the filtered shot of the gray card. Then use your white balance correction function in whatever application you're using to adjust until the filtered image of the grey card is properly balanced. Record the differences in white balance correction to each image and you can then apply the same amount of correction to your original images.