Why is the TDS on my RO system so high?
With your 40 years experience in drinking water, I'm hoping you can help. At this point I'm worried and confused about the new drinking water system we just had installed in our home by a local company that we will be renting from.
For the past 17 years we have been renting a Reverse Osmosis system (4 Stage) from a company that does supply or install ro/alkaline filter equipment. Our equipment is under the kitchen sink. I thought RO water was healthier for myself and my family. I recently read that RO water is Acidic water because it takes all the minerals out. I was told by a friend that adding an Alkaline filter to our RO system would make the water more alkaline which is healthier for the body. This past Wednesday, I had a 6-Stage Reverse Osmosis/Alkaline Ionized Water filter system installed by a different company. I read it would be healthier because the alkaline filter adds Minerals back into the water which makes the water more Alkaline. Drinking a more alkaline water supposedly makes the body less acidic.
The RO water I had before always tested between 10-20 (company serviced every year or sooner if needed). I have a HM digital TDS meter tester and would check it myself now and then.
The new company is family operated. The wife did a lot of research before adding this alkaline ionized filter to their RO systems. She claims it's one of the best filters out there. Her older son takes care of the water system for the military so I thought this was a great testimonial.
Before they installed our new system, we tested my water from my "old" RO water system, it tested 12, both on my tester and his. After our new RO/Alkaline Ionized filter water system was installed it tested at 49. He said it's higher because of the minerals added back into the water. He also told me to drain the tank tonight and in the morning re-test the water, it should be much lower probably in the 20's. In the morning it was 72. This made me worried about drinking this water. I called the owner and she was surprised that it was that high & said she would call the manufacturer and get back to me. I tested the water again this morning, and it's even Higher, 96. As I said at the beginning of this long email, I'm worried about this water and don't know if we should be even drinking it.
When I saw your site and with all your experience in this field I thought you could tell me what's happening & if we should be drinking this water. We also buy bottled water to take out with us. We buy "DaSani" water. I tested the DaSani, it was 24. DaSani claims they add a very small amount of minerals back into their RO water for taste. I thought 24 is a pretty good # for bottled water. Which makes me more confused as to why my new system is testing out so high.
I hope you can help. I would be more happy to pay you a fee for your unbiased opinion on this water situation, please let me know. It would be worth it for someone with your experience.
I.S. - Westlake Village, California
The Water Doctor responded:
First of all, the debate about Alkaline verses Acidic water is sad, because most people do not understand the difference, and there are lots of unscrupulous companies competing for the business. For the record, I do not think a few points on the pH scale make a difference because you drink the water and the water penetrates the cell wall, it becomes the pH of the body anyway.
You have evidently purchased a reverse osmosis system that adds minerals back to the water (usually calcium carbonate) which is why your TDS is higher than before. Your RO is taking the minerals out and the re-mineralization filter is adding some back. It is functioning perfectly in all likelihood. No matter what the label says, you do not have a Alkaline Ionized filter. You have a RO system where additional minerals are added which adds TDS (Total Dissolved Solids) back to the water.
Some manufacturers say that they have ionized alkaline water, but unless the ORP (Oxidation Reduction Potential) is lowered and the pH (potential of Hydrogen) is raised and alkalinity added, you cannot change the alkalinity. The water may be alkaline in nature (pH above 7.0) but it does not add alkalinity and there is no benefit to that.
The people you bought the RO from are probably innocent of any deception, simply uneducated about these things, but just adding minerals to raise the pH (and TDS) really does nothing. To have alkaline water, you would have to use an alkaline water ionizer (an electrical device that uses electrolysis), but that may not be wise either, simply because you can't use RO water to make alkaline water. You have to leave the contaminants, and then you concentrate all the impurities removed by reverse osmosis. A good ionizer can cost up to $7,000.00! Silly, in my opinion when you can simply do one of two things:
- Use 1/2 teaspoon of baking soda in 12 ounces of water once a day; or
- Use Gerolsteiner Mineral Water once a day.