Why is the TDS on my RO system so high?
Dear Sir,
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.
Regards,
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.
49 Comments
Hank,
There may be some typos – I am not sure. Can you re-frame your question?
Lol….4 sure. I may have meant that for a different site….
This question/issue doesn’t have much to do with this article.
What i was trying to say is….my urine ph usually tests at 5.5
If i add the soda to ro water and drink it, does it end up pulling minerals out of my body? Reason i ask is i can go upto a tbsp of soda to 20oz of water, do that for a few days, stop for a few days, then check ph and it goes down past the original 5.5…its gone to 4.5 a couple of times…I drink 20 oz of water with a half tsp of baking soda, the ph shoots to 7 or higher
Its obviously not good to have urine ph of 5.5.
I was trying to ask if im drinking water with a good amount of alkalinity my ph should go up right? the body will balance/buffer mineralized water better than ro water with baking soda, right?
I understand you’re not a dr and cant give medical advice. Have you heard of this happening to others?
My thought is the ro doesn’t gain minerals from the baking soda, its pulling minerals out of my body at the same time its giving me a false ph reading because of the high ph from the baking soda water…if that doesn’t m ake sense im going to get checked for dyslexia….lmao!
I am not a Doctor, but water is not a significant source of minerals. I do know that when water penetrates your cell wall, it becomes the pH of your body. If you drank a bathtub of water a day, you might get 5% of the minerals your body needs, so it seems silly to re-mineralize when you could just take a supplement to get better results. I think you are looking for something where there is nothing there.
Can you re mineralize ro water with baking soda? My guess is no…so i would have to buy a calcium/mineral supplement with the sole specific use to remineralize the ro water?
The baking soda just adds alkalinity and adjusts the ORP.
Why do you want to re-mineralze?
So Mr Water Doctor if I take 1/2 teaspoon baking soda in 12oz of water once a day or use Gerolsteiner Mineral Water once a day should be enough??
I am not a medical doctor, but I know people who do that with success. I am not advising you for or against it. You should talk to a health professional.
I have an generic 3 stage undersink RO. sediment – membrane – post carbon with permeate pump. i have traced all lines and i am satisfied all are connected properly. MY Tap water (originally from well) is 502ppm. RO is 330. I’ve never been able to get it below 125. I just changed both filters and membranes, drained system multiple times to flush. Before i changed the membrane, the TDS was matching the tap water suggesting a damaged membrane (pass through). Is the post carbon the culprit for keeping the TDS so high? any other suggestions.
Chris,
It sounds like a design or manufacturing flaw. Post carbon should not have any effect, but if it’s only a three stage, I would question the pre-filtration if you have a post carbon filter. Can you send a photo of it?
Christopher,
did you run at least 5 gal out of the ro side after you installed it? I’ve seen similar issues when people did not run enough water through the entire system before testing the TDS.
Hello Mark,
I have RO system installed to use to produce cosmetics. TDS reading after installation was 0 ppm but after 2 weeks rise to 86 ppm.
It is still ok to use this water to production?
Barbara,
I would think not and you need to determine why the huge rise in TDS? Is it lack of pre-treatment that fouled the membrane? I need more information.
This is a wonderfully helpful post and comments. I’ve just installed a countertop New Wave Enviro 10 Stage Water Filter System and tested with a TDS stick. It’s testing in the 100s. I tested water from a Zero Water pitcher and it was 0. Is the 10 stage filtered water safe to drink?
Thank you!
I can’t say whether it’s safe or not, but contaminanted water can read ZERO. TDS is not a measure of purity – it is a measure of the minerals in the water. Zero Water is ZERO TDS because it uses Deionization to remove all the minerals. Zero does not mean it is good to drink or even safe to drink. It just means that it has ZERO minerals.
Hi Mark,
I just bought the TDS tester. I’ve tested the Tap water and the reading is 55 ppm, while RO water is 43 ppm. Is it normal? Can I use the TDS calculation to prove the quality of the RO water (by rejection rate) if the reading as mentioned?