The way that I understand it, the problem with the French-side water is not at the desalinization plant. The water at that point is potable, and free water is available there. The problem arises as the water travels farther out into the network. My non-engineer understanding is that it is a chemical reaction caused by a combination of the Bromides which naturally occur in seawater, the chemicals used to purify the water, and heat.

A similar problem on St Barth took over a year to be resolved. It appears to be difficult to get right, as changes in the treatment system can have other unintended results farther down the line.

I have never seen a statement as to whether the existence of Bromates in the Fench-side water was determined by new testing, or if the same testing has been taking place for years, and the existence of Bromates is new.

Likewise, I've never gotten a good answer as to whether or not the Dutch-side water is tested for Bromates.

The article which Carol linked says that private testing has pronounced the water to be Bromate-free. I've seen mention elsewhere that the testing by the ARS (regional health authority) has also determined the water to now be Bromate-free.