OK to drink DI water?

[debdp]

We used to drink the RO water quite regularly for a couple years until I read about the possible issue with minerals. So, I added a 4 stage 75gpd unit that I use drinking water filters in (coconut fiber). It also serves as a backup in case there are issues with the 100gpd RO/DI unit used for the aquariums (which did happen, I just had to switch out the filters). While I always cleaned out the canisters using vinegar, I never thought to sanitize the whole unit. So, something to do on my next filter change. Thank you for posting this.

 

[jdegrasse]

Yes, there is a small reason, IMO, but it is not what you think.
But, my possible concern is that the water no longer has any protection from bacteria after the water passes through the RO membrane, and post RO water is known to have bacteria in it (not from the source water, but growing on the membrane and downstream surfaces). Consequently, while the risk may be quite low, my concern is microbial contamination, just as it would be from drinking any water that you left sitting in a container for a substantial period before drinking it. If you are going to drink stored RO/DI water, you might want it treated with a UV or some other way of sanitizing it. But again, the risk is likely quite low.

Hi Randy,
I agree that microorganisms can reenter the RO/DI water at any point after the RO filter.

However, I would think that it would be unlikely that the RO/DI water would be contaminated with pathogenic bacteria/viruses/parasites that would make one sick if one has a healthy immune system (not immuno-compromised). Those nasty critters are killed off in the municipal supply. If anything, heavily contaminated product water may have an off-color, -smell, or -taste that is unpalatable if there is excessive bacteria or fungus. In that case, I wouldn't drink it.

Jeff

 

[Randy Holmes-Farley]

Hi Randy,
I agree that microorganisms can reenter the RO/DI water at any point after the RO filter.

However, I would think that it would be unlikely that the RO/DI water would be contaminated with pathogenic bacteria/viruses/parasites that would make one sick if one has a healthy immune system (not immuno-compromised). Those nasty critters are killed off in the municipal supply. If anything, heavily contaminated product water may have an off-color, -smell, or -taste that is unpalatable if there is excessive bacteria or fungus. In that case, I wouldn't drink it.

Jeff

Yee, I agree the risk in drinking is low, but the FDA warns about microbial contamination in water used for more critical applications, such as dialysis:

Reverse Osmosis

from it:

It has been reported that bacteria can "grow" through membranes. The mechanism by which bacteria pass through a RO membrane is not known and no correlation exists between a dye leak test of the membrane and its bacterial retention efficiency. Researchers at the Center for Disease Control (CDC) conducted extensive investigations on the bacterial contamination of RO systems used in producing purified water for dialysis (15). They reported: 1. certain naturally occurring Gram- negative bacteria can multiply in relatively pure RO water; 2. thorough periodic disinfection of the entire RO system is essential in producing water with acceptable bacterial counts; 3. stagnant water in pipes down stream of the membrane is the major source of bacteria and endotoxin in the product water; and 4. the efficiency of a membrane in rejecting bacteria is better in continuous operation than in intermittent use.

 

[Killjoysgal]

I have had reef systems off and on for several years now, and make a point of changing the filters on the RODI system, but can anyone outline what is proper sanitizing practices?

If this has been outlined elsewhere, or a derail of the thread, I apologize!

-Amy

 

[jdegrasse]

Yee, I agree the risk in drinking is low, but the FDA warns about microbial contamination in water used for more critical applications, such as dialysis:

Reverse Osmosis

from it:

It has been reported that bacteria can "grow" through membranes. The mechanism by which bacteria pass through a RO membrane is not known and no correlation exists between a dye leak test of the membrane and its bacterial retention efficiency. Researchers at the Center for Disease Control (CDC) conducted extensive investigations on the bacterial contamination of RO systems used in producing purified water for dialysis (15). They reported: 1. certain naturally occurring Gram- negative bacteria can multiply in relatively pure RO water; 2. thorough periodic disinfection of the entire RO system is essential in producing water with acceptable bacterial counts; 3. stagnant water in pipes down stream of the membrane is the major source of bacteria and endotoxin in the product water; and 4. the efficiency of a membrane in rejecting bacteria is better in continuous operation than in intermittent use.

I agree that RODI water is not sterile. But, we know that not all microorganisms can make us sick.

That is from a document that serves as guidance for drugs and medical devices. Products from dialysis and the like pass right into your bloodstream without the benefit of gastrointestinal immune surveillance, and so proper medical sterilization is needed. So, it goes to my point that as long as someone isn't immuno-compromised, then all will be OK. Maybe flush out the RO/DI system if you haven't used it in a while.

I also want to add that there is no reason to sanitize an RODI unit unless you see evidence of bacterial/fungal growth or it has sat wet in a dirty basement for ages. A good indicator that your system is contaminated and needs to be sanitized is if you start the flow of water and the initial output is off color and smells bad. You may also see slime in the canisters. Otherwise, save your time. There is nothing about this hobby that is a sterile and there is a ton more things to worry about before one sanitizes a RO/DI unit.

 

[Reefedup]

I'm new at all this ro/di stuff, is there a difference in what I get at lowes vs one for aquariums? Also I read about the smell some get from storing the water, is it only noticeable at the can or does it consume the room? I was looking to set up a WC storage station in my laundry room. Can I store premixed saltwater in my brute can for say a month? Do I need to keep a pump in it to keep it moving?

 

[Randy Holmes-Farley]

I store unstirred new salt water for a month just fine.

Any RO/DI that produces 0 ppm TDS water is fine, but systems at places like Lowes may not have the features that can be useful, such as inline TDS meters and a pressure gauge.