Drought stricken HOA in CA banned from watering their own flowers

One of the questions I read was from an HOA member in Florida whose association was underwater, so the members took it upon themselves to physically do a lot of chores themselves, including taking care of the yard.

I am president of a 30 unit/3 building condo in CA where we have suffered from a drought. We had to fire our landscaper/gardner for being dishonest so one of our members has taken it upon himself to voluntarily water the yards twice a week on days allotted to us by the city. We've let our grass die, but we have flowers and trees.

One grouchy homeowner contacted our insurance to complain about this and they, in turn, told us we couldn't water our own yard -- we needed to pay an outsider who was bonded and liable in case there is a 3rd party accident. This seems ludicrous to me.

Is it lawful to not allow a homeowner to water his/her/our flowers and trees?