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Hardness FAQ

Water Hardness FAQ

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Water Hardness | Water Quality




Water Hardness FAQ - Question 1
Somebody left bottles at my house as part of a Community Water Test. Does the City of Columbia Water Works Department do this?

No. This is a private company that sells water-softening units. The Water Works Department will test your tap water if you are experiencing a problem, but only at your request. Contact the City of Columbia Customer Care Center at (803) 545-3300.




Water Hardness FAQ - Question 2
My neighbor had this test done and was told the City water is alkaline and hard. Is this true?

Only if compared to water that is acidic and very soft. The pH (acid/alkaline level) of tap water leaving the treatment plants is about 8.0, which is close to neutral. Completely neutral water is 7.0 on a scale of 0 to 14. Water less than 7 is considered acidic. City water is discharged slightly alkaline to prevent corrosion of water pipes and to help maintain adequate disinfection of the water, which is more effective at a higher pH.




Water Hardness FAQ - Question 3
Does Columbia have "hard" water? And what exactly does that mean?

"Hard" refers to a measure of difficulty - how hard it is to form lather and suds - and to the hard mineral deposit left on fixtures. "Soft" water uses less soap and detergent to form lather and suds, and can make clothing and skin feel softer.




Water Hardness FAQ - Question 4
What are these grains of hardness that people refer to?

Water hardness is expressed in one of two units of measurement. The first unit is parts per million (ppm) and the second expression of hardness is grains per gallon (gpg). A gpg equals about 17 ppm.




Water Hardness FAQ - Question 5
My neighbor said City water has a hardness of 1-2 gpg. I have no idea what that means. Is that hard or soft?

It depends on who you ask. The US Geological Survey established levels of hardness in 1962. These classifications are given below.

Classification Parts Per Million Grains Per Gallon
Soft 0-60 0-3.5
Moderately Soft 61-120 3.5-7.0
Moderately Hard 121-180 7.0-10.5
Very Hard 181+ 10.5+


Since the Columbia water is 1-2 gpg, it is generally referred to as moderately soft. Private organizations such as the Water Quality Association have changed the government classifications so that only water below 1.0 gpg is considered soft, and the level from 1.0 to 3.5 is called slightly hard. WQA is a self-monitoring trade association of the home and commercial water treatment industry.




Water Hardness FAQ - Question 6
What causes this hardness? Should I be concerned about some kind of contamination?

No. The level of hardness is determined mainly by the amount of two minerals, calcium and magnesium. From a health standpoint, these minerals have no adverse effects and are, in fact, essential daily nutrients. In addition, water contains trace amounts of vital minerals that are found only in minute quantities in the human body. Researchers have found that these tiny amounts can have a beneficial effect on human health.




Water Hardness FAQ - Question 7
Are there advantages to having extremely soft water?

Very soft water won't leave mineral deposits on pans or mineral scale buildup in hot water heaters. You will use less of household cleaning products like detergents, and less of personal hygiene products like shampoo. You may get longer life from appliances like dishwashers and washing machines.




Water Hardness FAQ Question 8
What about disadvantages to softening?

Softening units remove calcium and magnesium minerals and replace them with sodium. For each gpg of hardness removed, 7.5 milligrams of sodium are added to each quart of water, a possible concern to those on low sodium diets. Softened water is also not recommended for watering plants due to its sodium content.

Softened water increases the potential for leaching metal from pipes, solder and plumbing fixtures. Increased levels of copper, lead, zinc and cadmium are found in soft water, especially when it stands overnight in the plumbing system. These levels can exceed EPA primary drinking water standards, especially for brass fixtures and faucets. When the water from Columbia's sources is treated, lime is added to increase hardness and adjust pH, which helps prevent this type of leaching. In addition, a corrosion inhibitor is added to aid in the prevention of heavy metal leaching.




Water Hardness FAQ Question 9
Why would anyone soften City water if we already have moderately soft water?

As the home water treatment industry has grown in the US, the concept of water softening has often been misconstrued as a purifying and cleansing process. This is due largely to exaggerated advertising and to consumer misconceptions about water treatment. In reality, hardness minerals can be a nuisance at high levels, but they are not a threat to health.

If you have questions about the quality of your drinking water, contact the Water Works Specialist at 255-8160. You may also view the latest Consumer Confidence Report PDF document in English and español PDF document for hardness levels. For additional information, visit EPA's Drinking Water Website.




Contact Us
Contact Us

Drinking Water Request
(803) 545-3300
1136 Washington St.
Columbia, SC 29201


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