By Greg Reyneke, CWS-VI
Hard water is called hard for a number of reasons. Some say it’s because it is full of hard, rock-like inorganic mineral compounds like calcium carbonate. Others call it hard because it’s hard on the wallet, plumbing, faucets, laundry and appliances. I like to teach my team that it is hard to lather. Soft water is so called because it’s the opposite of hard and it sounds better than easy.
Water’s changing aspects
Some people don’t fully understand why different waters in different areas have differing hardness levels and why they can and will fluctuate over time. This is worth discussing. Pure water contains only oxygen and hydrogen molecules and is recognized as nature’s universal solvent. The hydrologic cycle is our planet’s natural water-recycling system, where water is constantly changing states between solid, liquid and gas, moving in the air, on the surface and even under the ground, constantly absorbing gases like carbon dioxide and dissolving metals and minerals as it comes into contact with them.
Water vapor in clouds eventually precipitates and heads down to the surface of the Earth. On its way down, it absorbs carbon dioxide gas, which makes it more aggressive. This naturally soft water is mostly devoid of hardness minerals; it generally has a low TDS content and low total alkalinity, meaning that it will usually be corrosive to plumbing systems and appliances without adequate treatment. When this water comes in contact with the Earth’s surface, it is exposed to organic and inorganic contamination. Organic contamination includes plant material, mold, fungus, algae, feces and other animal byproducts. This is one of the reasons why surface-sourced municipal water is typically more chlorinated than ground-sourced supplies. Water that percolates down into the ground moves through varying rock strata, where many live contaminants are filtered out. This process also extracts calcium, magnesium and other contaminants from the ground. The hardness level of this water will vary, depending on what kind of rock the water is exposed to, what types and volumes of entrained gases are involved and how long it stays underground before it is used.
Even small amounts of hardness minerals will cause the water to exhibit typical hard-water characteristics. The higher the hardness level, the more evident the problems will be. Residential and commercial users typically identify two ‘pain categories’ when dealing with hard water:
Laundering results aren’t satisfactory; dishes, glasses and silverware are not clean enough and larger amounts of cleaning materials are required.
How to overcome the problem
For over a century, salt-based ion exchange softening has been the gold standard in addressing these issues, since the technology is relatively easy to deploy and extremely cost-efficient to own and operate. Salt-based softeners are now even more efficient than ever before, especially with the advent of sensor-based upflow regenerated twin-softening systems that are becoming the new international benchmark for efficiency and sustainability. Even with these technological improvements in regenerant and water efficiency, some people can’t or won’t use a salt-based system and actively seek alternatives. While many alternatives exist in the marketplace today, it is important to remember that unless they are fixing the soap problem, they’re not really softeners at all.
One of the most popular soft-water sales tools is the simple soap test, where we compare the soap-sudsing difference between the good water that our system will produce and the prospective client’s untreated, utility-grade water. Even after two decades in the industry, I still enjoy observing this simple, dramatic difference in water quality that helps to educate consumers about the benefits of improving the water in their home or business. Seeing the beautiful suds being effortlessly developed in softened water reminds us that soft water is a significant improvement to the end-user’s quality of life and not merely something to address the pains of hard water. I consistently hear three questions asked about soft water. The quality of answers I hear from dealers, plumbers and some experts vary from amusing to disconcerting, so let’s explore some better answers together.
Is soft water corrosive?
Since water softened through ion exchange is devoid of hardness minerals, some misinformed people believe it exhibits the same aggressive characteristics as the naturally soft water discussed earlier. This is not true, since water softened through ion exchange retains its original alkaline characteristics while simply substituting hardness and other ions with sodium or potassium ions. If you’ve been in the soft water industry for more than a few years, you’ve probably visited a home or business that has a water softener and yet still suffers from premature water-heater failure or premature degradation of the sacrificial anode(s) within. This can indeed happen, especially if the softening system is malfunctioning by not rinsing all the regenerant or regeneration byproducts after regeneration. A good, safe guideline is as follows: As long as the influent water is within a pH range of 7.0 to 8.5 and the influent TDS level is less than 500 mg/L, you can take comfort in knowing that you are not going to make the water any more likely to be corrosive by softening it. At pH levels on the low and high ends of the spectrum, or where conductivity is elevated, corrosive conditions can occur with or without a water softener and should be addressed properly by someone with the requisite skill set. That’s one more important reason to always test the water you’re working with and to constantly seek more education and training.
Is soft water bad for me to drink?
Softened water does not contain sodium chloride or potassium chloride salt. During the ion exchange process, sodium or potassium ions are added to water in direct proportion to the amount of other ions being removed from the raw water. The result of this sodium addition is the formation of sodium carbonate and bicarbonate compounds in the water, which do indeed contribute to taste. At hardness levels < 15 gpg, many people describe the additional sodium as making the water taste sweet or well-rounded. At higher hardness levels, some drinkers begin to identify an alkaline or soda flavor in the water. If the water from a softener tastes salty, this is not normal, and the customer shouldn’t drink it.
Hypertensive persons, or those on sodium-restricted diets, are concerned about the total amount of sodium that they consume in a day. The process of softening water generally adds 1.86 mg/L for every grain of hardness removed, so when you soften 15-gpg water, you’re adding almost 28 mg/L of sodium to whatever is already naturally there. To put that into perspective, one teaspoon of salt contains approximately 2,000 mg of sodium and cow’s milk contains approximately 125 mg of sodium per cup. We’re not physicians and it is outside the scope of our expertise to provide medical advice to our clients, but it certainly is helpful to be able to supply real data to our clients when they need it.
While there are many arguments for and against consuming the inorganic minerals found in hard water, my personal decision is simple: since the inorganic minerals in water are so difficult for the human body to assimilate compared to the abundant and easily assimilated organic mineral compounds found in common fruits and vegetables, I choose to derive nutrition from food and hydration from water, while making sure that the water I drink is as pure as possible.
Why is soft water slimy?
The perceived feel of any water on the skin is primarily affected by pH. Lower pH waters will generally feel rough, while higher pH waters will feel smooth or even slick as the pH rises above 9, regardless of mineral content and before soap or detergents are even used. From our soap-bubble test, we know that soap behaves very differently in hard water than it does in softened water. Soap loses its cleaning ability in the presence of hardness ions and instead forms a sticky precipitate known as soap scum or soap curd. This precipitate clings to skin and hair, producing the characteristic squeaky clean feeling that many people have become accustomed to when living with hard water. The problem of course, is that squeaky clean, is really more like squeaky dirty, since soap precipitate and soil deposits are left behind on the skin.
Soap is typically manufactured by combining a fatty tri-glyceride molecule, such as lard, tallow, olive, soy or coconut oils to name just a few—each has a distinct effect on the cleaning, sudsing and lathering capacity of the soap, but more on that in another article—and sodium hydroxide (lye), which yields a molecule of glycerol with three ion-bonded molecules of sodium stearate. This will donate sodium ions to water, while the stearate ion will precipitate out of solution when it comes into contact with a calcium or magnesium ion that binds to it. This waxy stearate precipitate is the soap scum that we talked about earlier. When softening the water by ion exchange, users can almost immediately notice the difference in the feel of the water when they wash their hands, body and hair. Depending on the exact softening resin used, underlying water chemistry and type of soap(s) used, end-user descriptions can vary from smooth to luxurious to slick or even sometimes, greasy.
Don’t embarrass yourself by trying to explain that your client is now finally feeling their body’s natural oils or some other such pseudo-scientific nonsense. That old myth needs to fade away along with calendar-based softeners, lawn darts and other outdated concepts. The real science behind feel is simple. We are introducing sodium or potassium ions into the water and they make it harder for the stearate to yield up its own sodium or potassium ions. Instead, the stearate clings to the slightly charged surface of your skin and the slickness is noticed almost immediately. Switch the soap to a potassium-base or change regenerant and there is a significant reduction in the perceived slickness in the bathing experience. It is also good to note that various soaps have different pH levels, so the client’s own soap can sometimes raise the pH so much that it feels slick, even in hard water.
Soft water truly is the investment that pays for itself. Our industry is almost 110 years old, and we are all still learning how to do our jobs better and more profitably. Keep learning and keep helping your clients by improving their water and their lifestyles. They will thank you and come back for more. Remember, you’re the expert they are depending on to help them make the best decisions for the health and safety of their family, a great responsibility that should not be taken lightly.
About the author
Greg Reyneke is Managing Director at Red Fox Advisors and has two decades of experience in the management and growth of water treatment dealerships. His expertise spans the full gamut of residential, commercial and industrial applications including wastewater remediation. In addition to cleaning water, Reyneke consults on water conservation and reuse methods that include rainwater harvest, aquatic ecosystems, artesian spring development, graywater reuse and water-efficient design. He is also a member of the WC&P Technical Review Committee.