Rain water.
I agree with kyrsyan one has to divert the first few minutes of rain away from your collection barrel so you don't get bird poop, bugs and roof grit in your clean collection barrel.
Clorox or bleach will help with the bugs and algee so your good there, you just need to stick your head out in the rain and bypass the first runoff away from your barrel.
I would think a pair of ladies nylons zip tied over the end of the downspout would catch most of the gunk from the roof and still let the water flow into your barrel Jeep!
A good friend has a whole house cistern collection system with twin 500 gallon tanks buried under their wooden deck on the back of their house out in the rural county area away from city water.
She does not bypass at all, she wants every drop of rain water in her tanks!
She uses a whole house filtering system with charcoal and media filters in the basement to filter out the bird poop.
They also use swimming pool chlorine tablet floaters in each tank to keep the moss, scum and creepy crawlers from taking over in the tanks...
She has been doing this for over twenty years now and she only complains when she has to have water delivered at $80 bucks to top off both tanks, she did say a light rain or an afternoon thunder shower will fill both tanks quickly and her house is maybe 1200sf.
Oh and once every couple of year her husband has to pressure wash the holding tanks to get rid of the scum build up in the heat of the summer...
Good luck Jeep!
SIRR1
