Rain through RO/DI

[Menace2Sobriety]

I've collected about 1300 gallons of rain water at work over the past week (big warehouse = BIG roof!

Anyway... I was thinkin of running through an RODI unit for my tank. About the ONLY argument AGAINST this I've found online is "acid rain". A simple pH test strip should prove a neutral PH (before filtering). If the water tests neutral would it be a safe way of free water? I'm on metered water at home so the 75% waste is.... Well.... A waste lol.

Menace

 

[87ford]

You don't have to waste the ro waste water you could use it to water plants and your lawn or garden I'm no expert but my concern wouldn't be just acid rain it would be what ever could possibly be on your roof that could leach out dangerous chemicals that even the rodi can't take out that would be my only concern cause even if you used new filters it could exhaust them within minutes and unless you have a really good laboratory to check for things we fishers would not be able to check for I would say our on rough ground you could always buy a cheap fresh water fish and see if he lives lol jk but like I said I'm no expert I'm sure they will chime in soon

Tom

 

[disc1]

Putting that through a RODI would be no different than putting any other water through. It might even be better than tap if you're really starting off with cleaner water to begin with. Filters might last longer. The end product will be the same either way.

The only caveat is the one you already hit on. If the pH is low it will burn through DI resin super fast and probably end up costing more than the water would have. If the pH is lower than 6.5 or so you might want to bring it up just over 7 just to save on the resin.

 

[dkeller_nc]

One thing that you may wish to consider is that there is probably a good bit of bacteria, pollen, dust, organic pollutants and other things in that collected water that wouldn't typically be found in tap water.

David's correct - a well-functioning RODI system will take care of those things. However, using this water may quite rapidly plug your sediment filters and potentially exhaust your carbon filtration. Particularly if the collected rainwater starts growing a lot of bacteria (which it will unless steps are taken to disinfect it).

Unless you live in the Western US that is heavily affected by drought and/or you local municipal water is very expensive, using rainwater will likely not be economically favorable. It's also not likely to be environmentally favorable, either, given the electricity required to pump it and the potential for changing out sediment filters much more frequently.