Pure Water from the Sky

Hi Group,

I decided to start testing out the TDS of rainwater here in Virginia after we discussed that a little in another thread.

First test was with a copious, 12 hour rainfall. I used an old steel pot (probably a mistake as it has some pitting).

TDS = 007

Not too shabby! You can likely clean with that alone! I will conduct more tests.

Marc I would love to see what you come up with. The only thing is your steel pot. a 7 tds will pull metal out the steel. you need a polyethalean tank to get real results. If you need one I may be able to get my hands on a 500 gal tank. let me know.

Thats pretty cool Marc

I have wanted to do this for sometime from reading on the Cleanitup forum.

I was planning on using 55 gallon drums. I was hoping to be able to do it from the roof of our office… I just want to find away to filter away any debris or roof particles.

Any ideas?

I tried this awhile ago. I got a TDS reading of 5 in a plastic container.

chris, to filter the roof particles etc. away you need a drainage sock or you can use a pair of pantyhose. The blue 55 gallon drums are already made of polyehtalene

Oh cool

pantyhose… I never would have thought of that …



If you google “harvesting rainwater”, there are many pdf documents on how to set things up, filter, etc… Many articles. That’s why I don’t have anything to specifically link.


Click on the highlighted words to take you to the cartridges & filters.

Ok we had a bit of drizzle today so I tested it out… I got a reading of 4 tds

About 2 weeks ago, South Texas experience a heavy “mud-rain” that supposedly developed from some major dust storms down in Mexico. Just wonder what my tds would have been if I would have done the testing during that time period?

More Info

The first link is a company that I have done business here in the Durham Region.

Collect rain at the right time off felt roofing and you may get a low tds of 1-2, collect in heavy squalls and it can be abot 20-30 or feed it through a simple DI filter. I use basic blue sponge aquarium filtration and collect only when its low. Rain “feels” different to RO/DI. Try not to collect from concrete tiled areas. Some of my customers are impressed by the reduced carbon footprint/harvesting sales talk as it costs them nothing. I have a couple of commercial jobs because of it.

Hi Jeff,

Fancy meeting you here!

It was from you I first heard of rainwater harvesting and I instantly thought it was a great idea. It’s something I really want to promote.

Interesting that it helped you get a couple of commercial jobs through it.

How much rain do you manage to collect per month would you say?

Are you kidding? He lives near Wales - he could probably fill 6 Olympic size swimming pools in a week.

Larry - I also think the same as you, we have brown rain. I’m looking to get the rain harvesting going once I move house. But I’m sure even a sand filtrate medium would get me some decent water after passing it through the DI.

Hi Mark, I guess the answer is as much as you need.
Base your collection on how much you need per day and then find the roof space to provide it. One downspot diverter will collect about 4 litres per hour 5 diverters = 5X as much but you could also collect the whole downspout with a larger prefilter then DI filter it.
If it rains wherever you are you realise there are millions of gallons up there

Wales!! Yeah, I remember having a cottage break there. You’re right it rained all week!
Then again it rains half the time anywhere in Britain!

I really hope rainwater harvesting catches on in a big way.

When you think of the wasted water that an RO unit produces and the cost of DI resin to purify hard water, not only is it green (which is a selling point as already pointed out), but its so much cheaper!

I’m not using wfp much at the minute, most of my work is ground floor stuff, but I’m intending to go for some bigger jobs, for which I will need wfp.

I did a search on You Tube for Rain barrels and came up with some interesting stuff.

I caught this on one of Marks newsletters.

//youtu.be/Rainwater Harvesting System Installation | Innovative Water Solutions - YouTube

This is interesting too:

Jeff, I hear you manage to collect rain water at 000 TDS.

It would be great if you have time, to write up a brief HOW-TO guide to and post it up here. - I could put it up on our Rainwater Harvesting page too.

Hi Mark,
Catch it from an inert roof using a down pipe diverter when the TDS is low.

filter it through Aquarium sponge, put it in an IBC container or large butt, and use it.

Thats the basics, sorry to be late getting back to you but I am under a lot of work pressure atm. More later next week.

Not sure this will work but here is an open invite to my photo bucket album- if you have nothing to do. Photo Storage