Plants use 10-15 % of water, the rest goes as seepage. Keeping in view of shortage of Water.
Here is what I do.
Take a pet Bottle, make a small hole in the Cap, and a larger hole in the Bottom, fill with Water,
and press the Head in soil at 45 degree angle, it will start drip action, keeping the soil moist round the clock. It will take a week or more to consume. This can be done in Flower Pots ad in Flower Beds. In flower beds keep a distance of a yard apart.
I had done this when I left for a week for upcountry. My plants were all fresh on my return