[paul alan]

I recently watched a documentary on weather done by Richard Hammond.

https://www.bbc.co.uk/programmes/b04vr2p4

Whislt talking about dust he stated that without dust there would be no rain, as the water molecules in the sky needed dust to combine with them in order to be heavy enough to fall from the sky.

So how clean is our rain water?

[nathankaye]

I recently watched a documentary on weather done by Richard Hammond.

https://www.bbc.co.uk/programmes/b04vr2p4

Whislt talking about dust he stated that without dust there would be no rain, as the water molecules in the sky needed dust to combine with them in order to be heavy enough to fall from the sky.

So how clean is our rain water?

Theres plenty of people who harvest rain water for various reasons.
Ive collected water in a clean cup before and tested the tds and i found on that particular day that it was 004.
Be worth keeping this thread ooen so wben it does rain if we all reportthe tds it would be interesting

[Arnold Palmer]

I tested rain water years ago, IIRC it was 002

[Dry Clean]

Dust and dirt has nothing to do with tds, your rain water could be filthy and still have a low tds, for something to show on your tds meter it has to be able to dissolve and also be conductive, for example sugar doesn't show up on a tds  reading.

[lee_dewing]

If I had the room to harvest rain water I would filter it through resin.

[Marc Stock]

I actually did this for a while. And it works very well.

Hooked my IBC to the gutter outlet, and ran it directly through my DI. Problem is that we just dont get enough rainfall when you need it and i had to keep putting the ro on to top it up, and i ended up with a mossie infestation in the van last summer it was a nightmare so evenutally after 2 years of using rainwater i dismantled it and went back to ro only. Plus it makes the tank filthy green and cloudy. But no spots on windows.

To do it properly, you need to pump the rainwater through a high wattage UV system, and then through another ro again to di it into a 2nd tank before using it in your di in the van And this is costly, you might aswell not bother.

Its a bit of a ball ache. And you kinda need sustained rainfall every week.

[Marc Stock]

Dust and dirt has nothing to do with tds, your rain water could be filthy and still have a low tds, for something to show on your tds meter it has to be able to dissolve and also be conductive, for example sugar doesn't show up on a tds  reading.

This is 100% correct.

Undesolved solids is turbidity