Why Alkaline Water leaves a White Residue

If you own a water ionizer, you no doubt have seen that alkaline water leaves a white residue, similar to hard water deposits, on glasses and cookware. You may also have noticed that the white residue left behind by alkaline water builds up quicker than ordinary hard water deposits.

alkaline water white residue infographic

That white residue? It means that your alkaline water is chock full of healthy minerals

The reason for this is that the mineral hydroxides in alkaline water are more hydrophobic – harder for water to dissolve – than the mineral carbonates in tap water. Because mineral hydroxides are more hydrophobic, they settle out of the water faster than mineral carbonates, so they build upon glasses and cookware faster.

The FDA’s position on mineral hydroxides

The mineral hydroxides in alkaline water – calcium hydroxide and magnesium hydroxide – are good for you. According to the FDA, both calcium hydroxide and magnesium hydroxide are commonly used in food and supplements as nutrients. For example, calcium hydroxide is used in baby formula and orange juice to fortify them with calcium. The FDA lists both of them in it’s Generally Recognized as Safe (GRAS) database.

FDA GRAS information on calcium hydroxide

FDA GRAS information on magnesium hydroxide

Amount of mineral hydroxides you get from alkaline water

The amount of mineral hydroxides you get from drinking alkaline water is about 10 – 20% of your daily needs for calcium and magnesium. To estimate how much calcium and magnesium you get from your water, you will need a copy of your local water quality report. The information you need:

  • Amount of calcium in your water in mg/L or ppm
  • Amount of magnesium in your water in mg/L or ppm

mg/L stands for: Milligrams per Liter

ppm stands for: Parts per million

Click here for a free local water quality report

ppm and mg/L are two different names for the same thing, the measure the amount of a substance dissolved in water. They are also equal: If you have 50 mg/L calcium in your water, you have 50 ppm calcium in your water. So they are interchangeable.

The amount of calcium or magnesium in your water in mg/L or ppm is the amount of calcium or magnesium you get from drinking one liter of water. So if you have 50 mg/L (or 50 ppm) calcium in your water, and you drink 3 liters of water per day:

3 (liters) x 50 (mg/L or ppm) = 150 milligrams of calcium. So three liters of water with 50 mg/L or 50 ppm calcium gives you 150 milligrams of calcium per day. It works exactly the same for magnesium. There is usually a greater amount of calcium in your water than there is magnesium.

Daily needs for calcium and magnesium for adults

Calcium: 1000 mg per day

Magnesium: 400 mg per day

Takeaway: You can get about 10 – 20% of daily needs for calcium and magnesium by drinking alkaline water.

How to clean the white residue from alkaline water on your glasses and cookware

The white residue is alkaline, so it dissolves readily when in contact with something acidic. Simply add a little vinegar to water, fill the glass or another container with it, and let it sit. The residue will dissolve and/or become easy to wipe off in a few minutes.

Does the white residue build up in my water ionizer?

Yes, but there are things you can do to keep it from becoming a problem.

  • Make acid water – This reverses the current flowing to the plates, it will help release any deposits on the plates
  • Run the ionizer’s cleaning function once per day – Advanced water ionizers like Life Ionizers will have a cleaning function to break deposits free of the plates
  • Follow manufacturer’s instructions – for cleaning your ionizer.

How a Life Ionizer deals with the white residue

Daily: Life Ionizers use a patent-pending Reverse Action Dual Cleaning (RADC) technology which uses a reversed pulsating current to shock deposits from the plates. You should run the RADC cleaning cycle once per day.

At filter change: When you change a filter, you should run a Life Ionizer cleaning cartridge to dissolve built up deposits in your ionizer. The cartridge cleans more than just the plates, it also helps dissolve deposits in the ionization chamber, on the UV light disinfection module, and in the ionizers internal tubing.

By maintaining your Life Ionizer properly, you will keep mineral residue build-up from becoming a problem, and be able to enjoy the health benefits that you get from the essential minerals that you get in every glass of alkaline water.


Is your water right for use in a water ionizer? Some tap water isn’t! To find out, call us at 877-959-7977 today for a free, no obligation water quality consultation


  • Basimah says:

    Should I run acid water through the ionizer for how long to clean filter. The water is completely Mh outdo cloudy on 9.5. What do I need to do to clean filter? Or shall I purchase a new one?

  • David Mcbride says:

    Thank you this page was very helpful and understanding the machine I have what it does and why it does what it does

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