OK, we all know about rain barrels, collect rainwater from your roof via your downspouts.
However...can it get more elaborate? If you have a walkout basement, and your back porch is the "low point", theoretically, a lot of your property's runoff would go there. Why not put a drain in your porch that runs into an underground storage tank?
Or, if your property slopes downward to a low point, put a drain there that would collect the runoff for use later? That way, all the water and soil nutrients that run off can be "recaptured" for your own use!
You might not want to bathe in it, but for irrigation it might work quite well!
However...even as I brainstorm, I have some potential issues:
1. Dirt. Runoff has dirt in it from your lawn, garden, etc. Dirt that can clog up distribution pipes, hoses, irrigation systems, etc. Can an effective filtering system be made to remedy this? Not to mention potential chemicals like fertilizer...but again, I'm saying not to bathe in it. It would be to go right back onto the plants it ran off of to begin with when a dry spell hits.
2. Moving the water. Gutter water naturally flows down with gravity. If you're collecting water from the low point in your yard, you may have to pump it back UP somehow to a tank on another part of the property.
Am I on to something here?? Or...has it been done?