In order to determine if you have hard water, you will often have to convert dH to PPM. This is the conversion from degrees of general hardness (or German degrees) used internationally to parts per million hard water unit, primarily used in the US.
To help everybody out with this conversion, we have created these three easy-to-use resources:
- dH To PPM Calculator. You just insert water hardness in dH, and the calculator will automatically convert that to PPM.
- dh To PPM Chart. This is a conversion chart where we have converted dH from 0 to 50 dH into PPM. In the chart, we have denoted soft water (0 to 3.37 dH) with this green color, moderately hard water (3.38 to 6.74 dH) with this light blue color, hard water (6.75 to 10.11 dH) with this blue color, and very hard water (over 10.12 dH) with this dark blue color.
- Water hardness dH chart. Lastly, we will look at how many dH is hard water; you can just look at this chart, use the calculator and/or chart, and check how hard your water is.
Water hardness scale in terms of PPM. Below 60 PPM or 3.37 dH, we have soft water.
Let’s first look at the water hardness units we are using in this conversion:
- dH or degree of Hardness (also referred to as the degree of General Hardness (dGH) or German degree) is a unit of water hardness equal to 10 mg/L of calcium oxide (CaO).
- PPM or Part Per Million is a unit of water hardness equal to 1 mg/L of calcium carbonate (CaCO3).
As we can see both of these hard water units are determined in terms of milligrams per liter, but the dH refers to CaO while PPM refers to CaCO3. For conversion, we need to use this dH to PPM formula:
PPM = dH × 17.848
That means that 1 dH is equal to 17.848 PPM.
Example: Let’s say that our water has 5 dH of water hardness; how much is 5 dH in PPM? We just insert 5 dH in the equation like this:
PPM (5 dH) = 5 × 17.848 = 89.24 PPM
This is just one example. To help you with the calculation for all other dH values, you can use the calculator, complete with the conversion chart further on. As we will see in the water hardness dH chart (at the end), 5 dH is considered moderately hard water.
dH To PPM Calculator
Here is an example of how to use this conversion calculator: Let’s say we want to convert 3 dH to PPM. Just slide the slider to ‘3’ and we get the result: 3 dH is equal to 53.54 PPM.
Here is the complete 0 to 50 dH conversion chart (resulting in 0 to 892.4 PPM):
dH To PPM Conversion Chart
| dH (degrees of Hardness or German Degrees): | PPM (Parts Per Million): |
| 0 dH | 0 PPM |
| 0.1 dH | 1.78 PPM |
| 0.5 dH | 8.92 PPM |
| 1.0 dH | 17.85 PPM |
| 1.5 dH | 26.77 PPM |
| 2.0 dH | 35.70 PPM |
| 2.5 dH | 44.62 PPM |
| 3.0 dH | 53.54 PPM |
| 3.5 dH | 62.47 PPM |
| 4.0 dH | 71.39 PPM |
| 4.5 dH | 80.32 PPM |
| 5.0 dH | 89.24 PPM |
| 5.5 dH | 98.16 PPM |
| 6.0 dH | 107.09 PPM |
| 6.5 dH | 116.01 PPM |
| 7.0 dH | 124.94 PPM |
| 7.5 dH | 133.86 PPM |
| 8.0 dH | 142.78 PPM |
| 8.5 dH | 151.71 PPM |
| 9.0 dH | 160.63 PPM |
| 9.5 dH | 169.56 PPM |
| 10 dH | 178.48 PPM |
| 11 dH | 196.33 PPM |
| 12 dH | 214.18 PPM |
| 13 dH | 232.02 PPM |
| 14 dH | 249.87 PPM |
| 15 dH | 267.72 PPM |
| 16 dH | 285.57 PPM |
| 17 dH | 303.42 PPM |
| 18 dH | 321.26 PPM |
| 19 dH | 339.11 PPM |
| 20 dH | 356.96 PPM |
| 21 dH | 374.81 PPM |
| 22 dH | 392.66 PPM |
| 23 dH | 410.50 PPM |
| 24 dH | 428.35 PPM |
| 25 dH | 446.20 PPM |
| 26 dH | 464.05 PPM |
| 27 dH | 481.90 PPM |
| 28 dH | 499.74 PPM |
| 29 dH | 517.59 PPM |
| 30 dH | 535.44 PPM |
| 35 dH | 624.68 PPM |
| 40 dH | 713.92 PPM |
| 45 dH | 803.16 PPM |
| 50 dH | 892.40 PPM |
If you know how hard your water is in terms of dH (degrees of Hardness) and want to know how hard the water is in PPM, you can just read it of this chart.
Example: How hard is a 10 dH water in terms of PPM? Checking the chart, we see that 10 dH is equal to 178.48 PPM. The blue color will also tell us that this water can be categorized as ‘hard’.
Water Hardness dH Chart
To fully underhand if you have soft or hard water based on the dH (or PPM), you can consult this chart:
| Classification | degrees of Hardness (dH) | Hardness (PPM) |
|---|---|---|
| Soft | 0 – 3.37 | 0 – 60 |
| Moderately hard | 3.38 – 6.74 | 61 – 120 |
| Hard | 6.75 – 10.11 | 121 – 180 |
| Very hard | 10.12 Or More | 181 Or More |
Now you know that, for example, 2 dH water is considered soft water and 14 dH water is considered very hard water.
We hope this makes clear how to convert dH to PPM (hard water units). If you haven’t found the answer, you can give us some numbers in the comment section below, and we will help you out.