Hard Water Testing

If you are on a municipal water system, the water supplier can tell you the hardness level of the water they deliver. If you have a private water supply, you can have the water tested for hardness.

As a guide, 60% of the UK population live in a hard water area.

Most water softener companies will be able to supply you with a free water testing kit.

Once you’ve tested your water supply, the hardness of your water will be reported in grains per gallon, milligrams per liter (mg/l) or parts per million (ppm). One grain of hardness equals 17.1 mg/l or ppm of hardness.

Classification		mg/l or ppm		grains/gal
Soft		0 – 17.1		0 – 1
Slightly hard		17.1 – 60		1 – 3.5
Moderately hard		60 – 120		3.5 – 7.0
Hard		120 – 180		7.0 – 10.5
Very Hard		180 & over		10.5 & over