A little eco-confession. We emptied each pool after one or two uses. In mosquito-infested Washington, D.C., it is not a good idea to leave large water-filled objects sitting around.

Absolutely true! But, Jen, how about finding a second use for that water? Most houses aren't set up to use graywater (which is perfectly good for routing to toilets, lawn sprinklers, and other applications), but it's possible to change that. You could've specifically pointed out the issue here, rather than just shrugging at it...

But really, DC (as I recall) rarely goes so long without rain that a few gallons of water would matter to the lawn. The impatiens, maybe!