With more than 30 years’ experience in the residential and commercial water treatment space, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.
Hard water can be a confusing topic, and it requires a great deal of research to fully understand. There are few numbers associated with hard water, and understanding them is critical if you want to choose the correct water softener. In this article, we will explain some key concepts, what the numbers mean, and how this will affect your choices.
A Basic Hard Water Primer
Water hardness is caused by an elevated quantity of dissolved calcium, magnesium, and to a lesser extent, iron. You can feel hard water effects when you wash your hands, and there is a thin film or residue remaining. This is the mineral content that is left behind on your hands, and you may notice that you “need” to use more soap. The minerals that cause hard water inhibit the ability to form soap suds leading to the formation of “soap scum.” It’s easy to see the effects of hard water minerals on your plumbing fixtures, where you observe a build-up of limescale. The water spots left behind on your shower stall or the surface of your car after washing are mineral deposits that remain after the water has evaporated. The only surefire to get rid of hard water is to install a water softener, but there a number of numbers to consider first.
Water Hardness Numbers Explained
When you look at a water softener, you will notice that there is a hardness number. Water hardness is expressed by a unit of measurement, and there are two in common use, they are:
- Parts per million (ppm).
Parts per million of calcium carbonate, which is a dissolved concentration of calcium and magnesium. This makes it simpler to calculate water hardness, where the following is always true.
1 ppm = 1 unit of calcium carbonate dissolved in 1 million units of water.
Parts per million is equivalent to milligrams per liter (mg/l) which is useful when you want to make comparisons with water softeners that use grains per gallon (gpg).
- Grains per gallon (gpg)
Much like ppm, grains per gallon measure the number of calcium carbonate grains in a gallon of water.
Home Water Testing
If you’re an urban homeowner, you can check out your current water hardness level at your local city web page. If you’re a rural homeowner, you can buy a water hardness testing kit online. The two most popular options are testing strips and filtration kits. They are both easy to use, and the instructions are easy to follow. Both types of tests indicate the presence of hard water with a color change based on the severity of the problem.
Water Testing Results
If your water hardness testing strip or filtration kit indicated a measurement of 1 gpg (17.1 ppm) or less congratulations, you have soft water. But, if you have any number higher than this, you have hard water problems. The higher the number, the harder your water is, and the problems it causes will be more extensive.
A single grain per gallon (gpg) is equal to 17.14 parts per million (ppm).
When it comes to water hardness testing, you will notice that gpg is the most commonly used measurement. But, water hardness can be measure in gpg or ppm, and it’s helpful to understand the differences to make accurate comparisons.
The grain capacity of most available water softeners is in the 20,000 – 80,000 gpg range. But, you may need a larger or smaller water softener depending on other factors, such as daily water use and the number of people living in your home. The water softener must be carefully matched to your home if you want optimal performance and efficiency.
A Handy Water Hardness Guide
Dealing with these water hardness figures can be hard to visualize in a way that’s relevant to you and your home. So, we’ve put together this handy guide to show how ascending levels of water hardness affect the average home.
0-3 gpg: No Water Softening Required
As we mentioned earlier, a water test result of 1gpg or lower indicates that you have soft water. But, if you have up 3 gpg, the effects of hard water on your home will be negligible. At 0-3 gpg, you don’t need water softening at all.
3-7 gpg: Moderately Hard Water
When the gpg exceeds 3 gpg up to 7 gpg the water is categorized as moderately hard water. In your home, this would be noticed as patches of dry skin after washing, bathing, and showering. When you open your dishwasher, you may notice that your dishes are spotty (dissolved minerals) and attempt to wash them again with similar results.
7-11 gpg: Hard Water
Within this gpg range, the water is considered hard, and you’re likely to notice many problems in your home. The most obvious sign could be a build-up of a crusty white scale on your plumbing fixtures. This is limescale, it can be cleaned up with white vinegar and plenty of elbow grease, but it always returns because the water is still hard. This limescale is also building inside your plumbing pipes, where it narrows the pipe diameter leading to a loss of water pressure. Eventually, the plumbing pipe will be fully blocked, and a professional plumber will need to replace entire sections of pipe. You may also notice red/brown stains on your porcelain surfaces and in your laundry due to excessive concentrations of iron in your water supply.
11-15 gpg: Very Hard Water
This hard water range is considered to be very hard indeed, and you will notice all of the previously mentioned problems relentlessly.
15+ gpg: Extremely Hard Water
At this level, the water supply is simply impossible to use on a daily basis.
What Can You Do?
If your home water testing reveals that you do have hard water over 3 gpg, what can you do about the problem? City water suppliers don’t treat the water supply for hardness, and rural homeowners are responsible for their own water quality. But, there are many ways to treat water hardness with a softener or conditioner system. If you have excessive iron concentrations in your water, they can be removed with specialized water treatment systems. A pre-filter can also be installed to remove sediment and debris to protect the water softener and remove turbidity. If you’re concerned about the hardness of your drinking water supply, contact a local water treatment specialist for expert advice.