How to Test for Hard Water
You can do a fairly reliable unscientific test to see if you have a problematic level of hard water in your home by doing the following test with liquid dish washing soap:
- Take a clean empty plastic bottle having a cap (such as a clean, clear pop bottle);
- Remove the cap;
- Open your tap water faucet and fill the bottle about halfway with water (8 to 10 ounces);
- Add 10 drops of dish washing liquid;
- Shake well;
- If the soapy solution foams up quickly you are good and the water is not hard;
- If it does not foam up but instead creates a milk-curd-like or soapy film on the water surface then the water is likely hard.
- If you have hard water scale build-up on your shower door or white scale on your faucet aerator, this is also another indicator your water is too hard.
- Less than 1.0 = Soft
- 1.0 - 3.5 = Slightly Hard
- 3.5 - 7.0 = Moderately Hard
- 7.0 - 10.5 = Hard
- Over 10.5 = Very Hard