Have you ever pulled dishes out of the dishwasher only to find them clouded or gritty to the touch? Maybe you run them again and find that they’re still not looking their best. It’s not just frustrating, but mystifying too. Why aren’t your dishes coming out clean?
The common culprit is something called water hardness. It’s the same reason your hands sometimes feel filmy after washing them and the same cause of the cloudy white layer that accumulates in your shower.
What is hard water? We define water hardness as a measure of the levels of dissolved minerals in your water, primarily calcium and magnesium.[1] As the water evaporates, its high levels of calcium and magnesium are left behind. Over time, that residue builds, impacting your health, home, and appliances.
Read on to learn all about water hardness, how to test for hard water using the water hardness scale, and the impacts of hard water on your health and home.
Water Hardness Scale: How is Hard Water Measured?
The water hardness scale is a measure of the amount of minerals in your water supply – the level of these elements is what makes water hard. The water hardness scale ranges from “soft” to “very hard” and can be expressed in two different measurements: parts per million (PPM) and grains per gallon (GPG).
The parts per million measurement uses milligrams to determine the concentration of a substance in water. A single PPM is equivalent to one milligram per liter of water, expressed as mg/L.
According to the United States Geological Survey, the water hardness scale in parts per million is as follows:[1]
- Soft: 0 to 60 mg/L
- Moderately Hard: 61 to 120 mg/L
- Hard: 121 to 180 mg/L
- Very Hard: >180 mg/L
Grains per gallon, on the other hand, uses a measurement known as a “grain” to determine water hardness. A grain equals 17.1 mg. The water hardness scale in grains per gallon is as follows:[2]
- Soft: 0 to 3.5 GPG
- Moderately Hard: 3.6 to 7.0 GPG
- Hard:7.1 to 17.5 GPG
- Very Hard: >17.5 GPG
Signs and Impacts of Hard Water
Hard water impacts nearly everything it comes into contact with, including your health and your home.
Health
While hard water isn’t considered a health risk, it can be a nuisance. Hard water with high levels of minerals like calcium and magnesium can have the following impacts on your day-to-day life:
- Skin irritation: Washing your hands and body with hard water can upset your skin’s pH balance and leave skin feeling dry and itchy.
- Hair damage: Minerals can build up on your scalp and hair, making hair look and feel dull.
Home
Where hard water really leaves its mark is on your home. The accumulation of minerals can have lasting impacts, including:
- Resource waste: Hard water leaves spots on dishes and reduces soapy lather, requiring more soap and water to remove hard water stains.
- Appliance wear: Over time, hard water can cause pipe corrosion and damage to appliances such as your dishwasher, washing machine, and refrigerator.
- Limescale buildup: Minerals leave unsightly scale on shower heads, faucets, kettles, and coffee pots.
- Greater wear on clothes: Hard water can degrade and shorten the life of fabrics.
- Reduced water flow through pipes: As mineral deposits build, less and less water can get through pipes.
- Appliance wear: Over time, hard water can cause pipe corrosion and damage to appliances such as your dishwasher, washing machine, and refrigerator.
Where do all of these effects come to a head? In your dishwasher. When you have hard water, minerals accumulate on your dishwasher’s pipes and moving parts, reducing its efficacy. Dishes often need to be washed multiple times, significantly increasing everyday wear and tear. This all results in more repairs and a shorter lifespan.
If you’re repeatedly finding yourself unclogging your dishwasher, it might be time to check why your dishwasher isn’t working. If your water rates greater than 61 mg/L or 3.6 GPG on the water hardness chart, hard water may be to blame.
Reducing Your Home’s Rating on the Water Hardness Scale
Hard water is largely determined by the geological makeup of the areas that groundwater runs through. That means it can be localized to certain areas. The United States Geological Survey offers a hard water map in the United States that shows which areas tend to have greater concentrations of calcium carbonate. If you live in one of these areas, it’s likely you have hard water.1
Hard Water Testing
Ready to test for hard water? You can measure your water hardness using an at-home testing kit or by partnering with an independent laboratory through the Environmental Laboratory Accreditation Program.2
Methods of Dealing with Hard Water
There are a few different ways to reduce water hardness. If you’re a homeowner and have the means, water softening is a go-to solution. This can be done two different ways:
- Reverse osmosis filtration: A method of filtration that uses reverse osmosis to filter water through a filtering membrane. It’s designed to handle small volumes of water, like at your kitchen sink.
- Ion exchange: These filtration systems soften water by replacing calcium and magnesium with sodium. They can handle all incoming water to your home.
If you rent, or if a home filtration system is simply not feasible, it’s worth exploring cleaning products designed to tackle hard water. Finish® Ultimate dishwasher pods are specially designed to tackle hard water stains, burnt-on food, and more.
Water Hardness Scale: FAQs
What is a good water hardness level?
A water hardness scale rating of less than 61 mg/L or 3.6 GPG on the water hardness chart is considered “soft” and will reduce impacts on your home and health.
When is a water softener needed?
Water softener is needed to reduce impacts of hard water. If you’re noticing spots on your clean dishes, soap scum buildup in your bathroom, or issues with your appliances, it may be time to use a water softener.
What hardness of water is safe to drink?
Hard water is not considered a health risk, therefore, any hardness of water is safe to drink.
What water hardness setting should I use?
Some dishwashers offer wash settings designed for different water hardness levels. Refer to your dishwasher’s manufacturer settings to determine which water hardness setting is right for you.
Wrapping Up
Depending on your location on the water hardness map, hard water may be unavoidable. Through proper testing for hard water and these solutions, you can reduce the impacts of hard water and extend the lifetime of your dishwasher.
For an even better wash, explore Finish® products designed to boost your dishwasher’s performance and easily tackle food, grease, and hard water.
References:
- U.S. Geological Survey. "Hardness of Water." Water Science School, U.S. Department of the Interior,
https://www.usgs.gov/special-topics/water-science-school/science/hardness-water#overview.
Accessed 23 Sept. 2024. - Montana State University. "Interpreting Water Quality Results: Hardness." Montana Water Quality,
https://waterquality.montana.edu/well-ed/interpreting_results/fs_hardness.html.
Accessed 23 Sept. 2024.
