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How Do You Treat Acid Water?

by Mark Timmons November 01, 2017 9 Comments

You might have acid water if your copper plumbing looks green and corroded, if you sometimes have "pinhole" leaks in your copper plumbing or if you see greenish-blue stains on sinks, faucets, fixtures, or inside your toilet tanks. Any or all of these issues can indicate that you have acid water. Water with a pH of 7.0 is considered to be neutral. If the pH is above 7.0, the water is considered to be alkaline, but if it is below 7.0, then it is acidic. In general, water with a pH of less than 7 is considered acidic and with a pH greater than 7 is considered basic. The normal range for pH in surface water systems is 6.5 to 8.5 and for groundwater systems 6 to 8.5. Alkalinity is a measure of the capacity of the water to resist a change in pH that would tend to make the water more acidic. What's the big deal if water is acidic or alkaline you might ask? In general, water with a low pH less than 6.5 could be acidic and very corrosive. Therefore, the water could leach metal ions such as: iron, manganese, copper, lead, and zinc from the aquifer, plumbing fixtures, as well as the piping. Also, a water with a low pH could contain elevated levels of toxic metals, cause premature damage to metal piping, and have associated aesthetic problems such as a metallic or sour taste, staining of laundry, and the characteristic blue-green staining of sinks and drains. The primary way to treat the problem of low pH water is with the use of a neutralizer of some sort but you can also utilize an injection system to balance the pH.

Whole House pH Balancing Filter

A Calcite Filter is the most popular way to neutralize pH. The best way to do this is with what is called a Whole House pH Balancing Filter (pictured to the right). The water flows into a pressurized tank that contains calcium carbonate (usually called Calcite) and/or Manganese Oxide (usually called Coresx). At US Water Systems, we normally use Georgia Marble which is an extremely high grade of calcite mined from the "marble region" of Georgia. The calcium carbonate or manganese oxide is absorbed by the water and raises the pH. This method is best for water that has a pH of 5.5 or higher. The tank is equipped with an automatic backwashing valve that periodically (typically every 2-3 days) backflushes the calcite media (the opposite direction of the normal flow) to the drain for a few minutes to re-classify the media and remove any precipitated solids and/or iron. In the process of raising the pH in the presence of iron, some iron will precipitate out and needs to be backflushed to remove it. A calcite filter adds hardness back to the water, so in many cases, a water softener follows the calcite filter in order remove the hardness added in the neutralization process. If you are using a calcite type backwashing filter, you may need to soften the water after it so as to remove the hardness that the calcite adds back to the water, unless your water is naturally soft in the first place.

A backwashing type of pH Balancing filter is generally the best because every few days it backwashes for a few minutes to remove any dissolved sediment, iron and the like. It also is very desireable to have a backwashing filter so that the media does not channel and clog up or cake. An Uplow Calcite Filter can be utilizes, especially if the water is very clean, like in whole-house RO applications or in beverage or craft beer applications. We also offer a pH Neutralizing Filter System with a cartridge that can be refilled. This is often called re-mineralization and is also used for whole-house RO and craft beer brewing systems. At US Water Systems, we offer two sizes of backwashing pH Balancing Filters and our tanks have fill ports at the top of the tank so that you do not have to disconnect the control valve when adding media.

Proportional pH Balancing Injection System

The second method, which is superior on low pH water, but more costly, involves using a chemical feed pump to inject a precise amount of soda ash solution into the water to raise the pH to prevent the water from reacting with the house plumbing or contributing to electrolytic corrosion. The Proportional pH Balancing System (shown to the left) assures that the pH is uniform regardless of flow rate and does not add any hardness back to the water. The soda ash is FDA and NSF Approved and does not have any effect upon health or wellness. It simply just raises the pH. Of course, I always recommend that any water you consume should be treated with reverse osmosis which removes the largest spectrum of contaminants and protects you from numerous sources of contaminantion. This blog was originally published on July 2, 2013, but was revised on November 1, 2017.

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November 03, 2017 Dusta Waits

According to strips my well water is pH 10. But it is so acid it is destroying my clothes. Anything metal will rust.
Drinking it leaves an acid taste.
Soap does lather well.
I would deeply appreciate an understanding of this water.

November 06, 2017 Russell Keyser

I live in North East, MD. Do you cover my area. I would like a water test done and see what you recommend for me.

November 09, 2017 Bill

Do you cover Nova Scotia Canada ?

November 11, 2017 Mark Timmons

We cover the world.

Here’s the water test you need to start:

November 13, 2017 Mark Timmons

Well it can’t be acid if the pH is really 10, but I doubt that it is.

If you want a better understanding of your water, you need to do this:

Once we know EXACTLY what is in the water, then we can fix it!

November 16, 2017 Mark Timmons

70% of the Earth is covered with water. The rest is covered by US Water.

If you are not covered with water, we cover you!

November 17, 2017 Kevin

I just recently had an acid neutralizer installed as the old unit was not working. It’s a calcite downflow unit with a clack ws1 valve. My water specialist told me that as the pH was low for a long time, you should expect the water to be on “steroids” for a couple weeks and the pH will be somewhat high for about 2 week (9 to 10) depending on water use and will gradually normalize to mid-7 pH range. I just wanted to know what this is?

November 20, 2017 Jim Young

Mark, I recently installed same system as Kevin….Clack WS1 calcite feeder…after 40 years of maintaining a soda ash injection system to neutralize well water at pH 5.5. Since the Clack is not proportional control, can it overshoot a pH 7.0 target? If so, can that be regulated in some way? Getting used to slick water is a challenge. Have not checked pH since system installed (along with softener). Send link for your home oH test kit. Thanks.

November 22, 2017 Fred Nouri

Hello Mark. I live in Southern California, near Los Angeles. My house is connected to the city water system. About 7 years ago we installed a whole house water treatment system which uses salt. We started noticing blue rust around faucets recently, and when we boil water, it tastes bad. I have been reading this can be an indication of too much copper in the water, but the city water should not have excess amount of copper in nit and my neighbors do not complain about corrosion or bad taste of water. I am suspecting the treatment system and perhaps salt? Will switching to potassium fix the issue, should I replace the system (costly!)?
Thank you for your advice.

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