Whether you want the feature or not, it is here. Google Assistant can now work with bathtubs and faucets. For tubs, it's a relatively simple list of commands. You can ask these smart tubs to fill or drain for you. But you can't seem to adjust the temperature. Now, for faucets, there appears to be a bit more complication. The tap is presumed to have different "modes" with their settings because of the varied kinds of liquids and presets available. As 9to5Google points out, these modes could point out to temperature control or even water filters in kitchen faucets.
Smart faucets and tubs are on their way. Brands like Kolher and Delta offer smart versions of their products, so it might not be far off for these devices to get Google Assistant support.
Source: Android Police