To rain garden or not to rain garden

I've been waffling on big garden projects, excited to get going but unsure if I have the free weekends to put in the work. If I rush home from work I have about an hour and a half where I can work on things before the sun goes down. That will get cut down to 30 minutes once Daylight Savings hits. That's if it's not pouring rain. My big project contemplation right now is the rain garden. I want to put one in front and one in back. 

For anybody not familiar with rain gardens, this is how they work: instead of having your rain gutters empty into the storm drain you treat your storm water on your property. Water from your storm drain ultimately gets dumped into the river, where it's warmer than normal (which means it has less oxygen) and it's full of pollutants. All the critters in the river get stressed because they can't breathe and they're dealing with oil and chemicals that come off of our streets and roofs.

When you treat water on your property it gets slowly filtered into the ground water supply, the pollutants are reduced, and the rivers don't get inundated by water from all of our impervious surfaces (roofs, driveways, streets, patio slabs, etc).So you dig a pit where water can collect, plant it with native species, and mulch the hell out of it. Did you know that microbial activity in mulch helps break down some of the common pollutants in stormwater? TAKE THIS INFORMATION AND GO BE INSUFFERABLE AT DINNER PARTIES. Then you divert your gutters to drain into this instead of your storm drain.

Before you start planning your garden you need to do a percolation test, to see if your soil drains quickly enough to withstand one.

So you dig a hole. I thought I heard somewhere that it should be 12x12x12, so that's what I dug. It turns out I can't find any documentation saying that 12x12x12 is the way to go. So maybe I dug a larger hole than necessary? Ideally you're supposed to do your perc test in the spring when the ground is really water logged, but I can't be counted on to follow directions, obviously.

Then you fill your hole and let it drain completely. Then you fill it a second time and let it drain. Then you fill it a third time and set your timer for an hour. At that time you look at how inches of water drained and *that's* a pretty good indicator of your drainage. Anything over 2 inches per hour is good. 

Mine drained 8 inches in an hour. After two hours all but the smallest puddle was gone.

So now I'm worried that my property is *too* well draining and that I'm actually living atop a giant sandpit that will collapse once I install my rain garden. Worrying is what I do and, damn it, I'm good at it.

If your property won't accommodate a rain garden, don't worry, you can still be insufferable at dinner parties! You can plant a tree instead. They are super good at sucking up water on your property. True story.

Has anyone built one of these before? Should I wait until spring? Would you like to help me dig? (I'll bake bread and cookies!)

Or would you like to help me plant the 150 bulbs I ordered? I swear I don't remember ordering half of these which is why you should never, ever drink wine when there are plant catalogs in the house.