Biological water filtration

Does anyone use a pond with water plants to purify water? whether complete filtration or a part of the system...If so, can you share your details please? I was trying to think of a way to purify rainwater and was hoping that I could use a biological method to purify all but drinking and cooking water....might still need a mechanical filter as well.

This is an area I have worked on.
There is an enormous amount of information on the net.
Look at aquaculture as well.
Natural swimming pools, also use plants

Rainwater is pretty clean anyway.
My household in Australia uses 100% rainwater and I provide no treatment.
I do have a first flush system, and I have very large tanks 5000Gallons.
The big tank is the secret, water cleans itself with time.
A large tank allows fines to settle and they can be filtered out with a disc filter near the pump.
I have a topic on the site about rainwater.
Rain water collection

I hope this helps

Thanks!  Yes, there is a lot of info on this subject, but, to date, the only info I have found is about setting one up.  While learning how to set one up I also want to learn how to maintain it, what is going to be required in the future, etc. Many of the systems that I have seen using plants show them growing to 24" or so...most things that grow taller, lose their leaves at the base, which takes away from the purpose.