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Angi How To Test For Hard Water

Date Published: Nov. 12, 2019

Time: 5 Minutes

Having "hard water" means that your water supply contains high levels of minerals like calcium and magnesium. While hard water is generally harmless to drink, it can damage your boiler and clog your pipes, which are expensive to repair or replace (a new boiler can cost as much as $10,000!). To prevent these problems, use these steps to test for hard water.

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Tools & Materials Needed 
clear plastic bottle with a cap
liquid dish soap
1Fill bottle with sink water.

Fill your plastic bottle with about 10 ounces of water from your kitchen sink. Add about a teaspoon of liquid dish soap, close the plastic bottle and give it a good shake. If the soap foams up naturally, you probably don't have hard water and can end your test at this point. If it doesn't foam, but instead forms a milky film at the top of the bottle, hard water could be an issue and you need to continue the test.

2Ask local water company about their readings.

If you have public water, contact your local water utility and ask them for a recent hard water reading. If you have a private well, you'll need to test your water yourself. Contact your local department of health and ask them which labs in your area can test your water. You can usually send a sample of your water to them and have it tested for free. It's generally best to avoid home tests, which can be inaccurate and unreliable.

3Check your results.

Hard water is generally measured in grains per gallon (GPG) of dissolved minerals. If your water has more than 4 GPG, your hard water levels are considered high.

4Install water softener.

If you GPG is 4 or higher, it's a good idea to install a water softener to reduce your levels. A water softener can cost anywhere from $100-$3,000 depending on the model, method of softening and water volume requirements of your house. It's also a good idea to have your water softener professionally installed, which can cost $100-$600.

5Maintain equipment.

Once your water softener is installed, maintain it! To learn more, read: Water Softener Maintenance.