No! Dont use water at all!
Water will only augment the lipo chemical reaction. You must snuff the fire out with CO2 or sand.

The truth about LiPos is that provided they are manufactured correctly the typical and most common failure is related to human error.
Not matching up the charge profile with the chemistry, voltage, capacity, or over charging, over heating or poor solder joints. These are all contributing factors and any can lead to fires or just damage to the battery pack.

When I was involved with LiPo's professionally we sold millions of $ in battery packs and the failure rate from production is very low, less than 1%. BUT the customer service side product return failure rate was huge!
I tested all the packs and created failures on purpose with all kinds of packs. You cant believe how hard it is to make a pack self destruct. You have a lot of warning time and signals before the flames come out. Dead shorting a fully charged pack usually results in blowing off the tabs or melting a soldered plug but not blowing a pack up.

Anyway, sorry to say, in my experience every fire I have seen from a pack is the result of human error. Thats different from a failure in use because there is a whole other conversation on that topic.

Also use a steel box to store and charge LiPo packs but in reality any battery pack. I designed and tested a box specifically for this application. The result was a box with ventilation that would allow the pack to expand, react and blow out the air in the box to snuff itself out. Then the hot copper foil sheets and other materials will smolder for a while still very hot. Now you can pour some water on the pack if you wish because the lithium and other battery chemicals have burned away.