They do use a LOT of water! We've been fortunate to have a few overnight showers even though the days are hot. That's been the only thing saving me from extra daily waterings.
I wonder, can you set up a self-watering back up system? I'm considering something like the first method they describe here:
http://www.wikihow.com/Make-a-Drip-Irrigator-from-a-Plastic-Bottle
I've actually thought of doing that! The ones I planted in the ground get dried out so quickly. I think next year I'll set up an irrigation system like that because the ones in the ground are becoming a battle to keep alive.
I figure these are simple and cheap, so it's worth a try. At least it would provide a steady supply during the hottest / driest stretches of weather. August is generally our toughest month, so it'll be nice to have a 'plan B'.
This is an irrigation system that might interest you.
https://permaculturenews.org/2010/09/16/ollas-unglazed-clay-pots-for-garden-irrigation/