Based on the provided reference, water is considered hard when its total hardness falls within the range of 150 to 300 ppm.
Understanding water hardness is important for many households. Hardness refers to the concentration of dissolved minerals, primarily calcium and magnesium, in water. The higher the concentration of these minerals, the harder the water.
Here's a breakdown of water hardness classifications according to the reference:
| Water Hardness Classification | Total Hardness (ppm) |
|---|---|
| Soft | Less than 75 |
| Moderately Hard | 75 to 150 |
| Hard | 150 to 300 |
| Very Hard | 300 or higher |
The hardness of water can vary significantly depending on its source. For instance, water from areas with significant limestone deposits tends to be harder because limestone contains calcium and magnesium.
For those interested in converting hardness measurements, the reference notes that to convert the hardness of your water from parts per million (ppm) to grains per gallon (gpg), you simply divide the ppm value by 17.1.
