What Level of Water Hardness is Too Hard for Your Family?
Welcome to my comprehensive guide on water hardness and water softeners. I’m Andrew Miles, a certified water quality expert with over 30 years of experience in water treatment and environmental sciences while being a master plumber.

Water hardness tells us how many minerals are in our water; the more minerals mean, the harder the water.
There is an ideal water hardness for homes, and depending on which city or zip code you are in, you may need a water softener to balance it for you.
What is the Ideal Water Hardness?
Water Hardness Scale (Chart)
This Water Softener Hardness Scale tells us if the water is soft or hard on a scale based on how many minerals are found in it. This water softener hardness chart will be based on grains per gallon (GPG) and Parts Per Million (PPM) and will look like this:
| GRAINS/GAL | MG/L & PPM | CLASSIFICATION |
| Less than 1 | Less than 17.1 | SOFT |
| 1-3 | 17.1 – 51.3 | SLIGHTLY HARD |
| 3-7 | 51.3 – 119.7 | MEDIUM-HARD |
| 7-10.5 | 119.7 – 179.55 | HARD |
| 10.5-15 | 179.55 – 256.5 | VERY HARD |
| Over 15 | Over 256.5 | EXTREMELY HARD |
The water hardness scale begins with water classified as soft if it contains 0 to 50 mgL (milligrams per liter) of dissolved calcium. Moderately hard water contains 51 to 120 mgL, and very hard water is classified as containing more than 180 mgL.
Water at the high end of the water softness scale, with many dissolved minerals, can leave a residue behind that affects clothes washed in the water and can leave a film on dishware and glass shower doors. Spots or film left on glasses in the dishwasher is due to hard water.
Ideally, water hardness should be somewhere in the middle of the scale, around 7-10 gpg. This is the level at which water is considered “hard” but not so hard that it causes significant problems.
If your water hardness is outside of this range, you can take steps to correct it. For water that is too hard, a water softener can be installed. This will remove the dissolved calcium and magnesium from the water, making it softer. A calcium carbonate filter can be installed for water that is too soft. This will add calcium to the water, making it harder.
How to Test for Water Hardness in Your Home
Fortunately, there is an easy way to test for water hardness in your home.
You only need a water hardness test kit, which you can purchase at most hardware stores. Once you have your kit, follow the instructions to collect a water sample from your tap.
Then, simply compare the color of your water sample to the chart included in the kit to determine the hardness level.
There is also a way of testing water pH without a kit using cabbage.
TDS meters are also great for testing your water, we have a review of many popular TDS meters here.
Water Hardness for Metal Pipes
If your house has metal pipes, be aware that excessively soft water can accelerate corrosion, leading to potential leaks. Copper pipes, while more resilient, are not immune. In my professional assessments for numerous homes, I’ve found that maintaining water hardness levels around 80-180 PPM is optimal for metal piping systems. Hitting this perfect level of water hardness not only puts the brakes on corrosion but also lets your pipes live long and prosper.
Water Hardness for PVC Pipes
Conversely, for homes with PVC piping, which are less prone to corrosion, a softer water range of 20-80 PPM is more suitable. So for most homes, it’s best to keep water hardness between 20-80 PPM to protect PVC pipes while still providing good quality water.
From my experience in environmental science, focusing on soil and plant health, I’ve found that a bit harder water can actually do wonders for your garden and lawn. A range of 120-200 PPM in water hardness not only aids in delivering essential nutrients to plants but also promotes healthier and more robust growth.
Finally, when it comes to personal health matters like dry skin or hair problems, my advice has always been consistent – go for softer water. A range of 20-60 PPM in water hardness can significantly alleviate these conditions, offering a gentler and more beneficial water quality for personal use.
Factors That Influence the Ideal Hardness Level
A few key things shift the ideal water hardness range, and they do it quietly in the background. Your water picks up Calcium ions, Magnesium ions, and other minerals as it moves through local geological formations and deep aquifers. These minerals build your baseline hardness, which can swing up or down when seasonal shift or groundwater depth changes.
Your source water chemistry also plays a big role. When bicarbonates rise, you see more carbonate hardness, and when Total dissolved solids (TDS) climb near 100 ppm or 150 ppm, the water becomes more mineral-rich. That shifts how the water behaves in daily life—how it tastes, how it feels, and how steady it stays.
Even a small pH influence at pH 6, pH 7, or pH 8 nudges your hardness balance because the water’s equilibrium minerals react differently at each level.
Local regional geology and regional hardness maps also guide what’s “normal” in your area. Homes on private wells often get more source variation, while city homes depend on municipal treatment plants, water distribution lines, and even distribution aging, which can push hardness fluctuation during the year.
If you use water softeners, then softener settings, resin exhaustion, and installation settings change the final number coming out of your tap.
Temperature also matters. A warm temperature influence can pull minerals out of balance and increase scale-prone conditions, while cooler water often stays more stable.
Hardness Factor Snapshot Cards
The four key elements that truly shape your ideal water hardness level. When you understand these factors, dialing in the perfect balance becomes surprisingly easy.
Source Water Chemistry
How minerals and dissolved gases naturally shape the required water hardness level.
Geological Formations
How underground rock layers slowly add calcium and magnesium into the water supply.
pH Influence (Acidity)
How the water’s acidity level affects mineral behavior and the overall hardness balance.
Total Dissolved Solids (TDS)
How all the tiny dissolved minerals together raise or lower the necessary hardness range.
What Does Water Hardness Mean?
Water Hardness is the number of minerals (specifically calcium and magnesium) in your water. The more minerals in your water, the harder it is. Hardness can best be described as if the water will stick to your skin or roll off it. The harder it is, the more it will stick to your clothes and skin.
Hard water is not necessarily bad, but it can cause problems in some situations. For example, hard water can make it difficult to get soap to lather and leave behind mineral deposits on fixtures and appliances.
The softer the water is, the more it will roll off you and your clothes and leave your dishes crystal clear and your appliances and pipes running perfectly. The softer the water you have, the longer your appliances last because of not having mineral buildups inside of them.
ne the ideal water hardness for your needs is to consult with a water treatment expert.
How Will Water Hardness Affect My Family?
Water Hardness can affect your family if it is too hard or too soft. If it is too hard, you may notice faucets with little white crusty bits that are mineral deposit buildups. If this happens often, you may also notice water pressure loss in your home because mineral deposits can build up and clog pipes.
If your water is too soft, you may be rusting out your pipes, depending on what type you have for your house. You also may not have a very healthy yard or garden if your water is too soft due to plants not getting enough nutrients.
What are Acceptable Levels of Water Hardness?
The term “water hardness” primarily refers to the concentration of minerals like calcium and magnesium in water. Interestingly, the U.S. Environmental Protection Agency (EPA) hasn’t set a legal limit for water hardness, given that these minerals aren’t toxic. This lack of a legal standard leads to a wide spectrum of what is considered acceptable or ideal in water hardness levels.
To shed light on this, water hardness is generally classified as follows:
- Soft: Ranges from 0 to 60 milligrams per liter (mg/L) of calcium carbonate.
- Moderately Hard: Falls between 61 and 120 mg/L.
- Hard: Occupies the range of 121 to 180 mg/L.
- Very Hard: Exceeds 180 mg/L.
These categories help guide water utilities in delivering water that strikes a balance – not too hard to cause scaling in household appliances and not too soft. The EPA’s 2018 Water Quality Parameters echo this classification, offering a similar breakdown:
- Soft Water: Defined as having less than 75 mg/L of calcium carbonate.
- Moderately Hard Water: Contains 75 to 150 mg/L.
- Hard Water: Comprises 150 to 300 mg/L.
- Very Hard Water: Exceeds 300 mg/L.
For everyday activities like bathing, washing dishes, or doing laundry, water that falls in the moderately hard category (61-120 mg/L) is generally seen as ideal. Though preferences vary; some individuals find hard water preferable for bathing, citing a feeling of cleanliness and refreshment. However, it’s crucial to consider that hard water can lead to the accumulation of soap on skin and hair, potentially causing dryness and irritation.
For those who find their water too hard or too soft for their liking, there are practical solutions. Water softeners can effectively reduce mineral content in hard water, while systems designed to add minerals can increase the hardness of soft water. These solutions allow for a tailored approach to water hardness, aligning it with individual preferences and household requirements.
When Is Water Softener Needed?
A water softener is ideal when your water hardness exceeds 300 PPM or over 3+ grains per gallon. This is when you may notice changes in the water in your house.
This can range from the water pressure dropping, the taste of the water being different, the color-changing, mineral deposits building up quicker than they used to, or the dreaded pipe bursting.
The effects of using too hard of water can be a nuisance. Having hard water in your shower can cause dry skin and hair loss. It may also cause clothes to feel itchy because of the mineral buildup in your clothes when you wash them. While these are not always major, your skin is your first defense against diseases and should be taken care of.
Water Hardness By Zip Code
For reading this far, here is an interactive map for finding the water hardness by zip code for cities across the United States https://www.hydroflow-usa.com/water-hardness-map
FREQUENTLY ASKED QUESTIONS
Is 7 grains Considered Hard Water?
How Many grains of Hardness is in Soft Water?
If your water is under 3 grains per gallon, it is not necessary to soften it, because it is already soft enough and only considered slightly hard at 60 PPM. Either is great for your skin, but you will need to add extra nutrients for your garden and lawn to take care of.
How Do I Clean a Hard Water Scale?
Leave the rags on for at least half an hour, and then you will be able to start breaking them up with a non-scratch scrubber of some sort.