moses and the bathtub

Using water to shower, to do laundry - then turning it into a garden...
It's a sin to let all that water down the drain!
The bonus: having clean water at the end.

Here's how it goes:

The first treatment - a old bathtub or similar handy "instant pond"

It's filled with gravel (some soil mixed in)
Where we will have:

Phragmites australis - takes up a lot of nutrients, cleans water.
It's a mini constructed wetland. The reeds are good for making baskets too (which might be a bonus if we need to send a baby down the river in an emergency.


For the second treatment, I would like:

Calla Lilies, which are beautiful lilies native to my country and region where I grew up in. ALSO, they take up nutrients and clean the water.
I'm just not sure about having such a poisonous plant where babes are walking and crawling, grabbing and eating.

Well, the reeds are a good start.
Now, to find some bathtubs...