You can press the "Water Plus" button before the start of the load. If, you need to add water after the load has started, you have to press pause, press the Water Plus button, then start. FYI, you have to hold the button down for at least three seconds for the option to select. You may want to check it after more water has been added because it still may not be enough. In that case, you will have to repeat those step several times in order to get the desired amount of water. Which means you pretty much have to monitor each load to make sure it has the desired amount of water you need.