Hard water rarely announces itself all at once. It shows up as spots on glasses, a ring in the tub, soap that will not lather and crust on a showerhead. Those signs are a good reason to look closer, but they are not a measurement. This guide lists the signs, then shows how to get the figure that settles it.
Install Water Softener is an independent referral service, not an installer or plumber. When you send the form, your details go to an independent local water treatment pro who can contact you and prepare a quote.
The signs around the house
- Soap scum and poor lather. The U.S. Geological Survey explains that soap reacts with calcium in hard water to form soap scum, so you need more soap or detergent to get things clean.
- Spots and film on dishes and glassware. Water utilities describe hard water deposits building up on dishes, fixtures and basins.
- Crust on faucets and showerheads. Even water softened at the treatment plant can leave small tan deposits of calcium carbonate in pipes and on fixtures.
- Scale in pipes and water heaters. Utility water quality reports note that hard water can cause scaling in pipes and water heaters, and on plumbing fixtures.
- On a well: scaly deposits and soap that will not lather. EPA’s private well guidance lists these signs, with a softener as the treatment for hardness.
Stains that are not hardness
Colored stains point elsewhere. EPA’s secondary guidelines link reddish or orange staining to iron above 0.3 mg/L, and black staining to manganese above 0.05 mg/L. Tell a pro which color you see: it changes the treatment.
How hardness is measured
Hardness is given in milligrams per liter (mg/L; some reports print it as parts per million, or ppm) or in grains per gallon. One grain is about 17 mg/L, so 170 mg/L is about 10 grains per gallon. The USGS grades it:
| mg/L as calcium carbonate | USGS grade |
|---|---|
| 0 to 60 | Soft |
| 61 to 120 | Moderately hard |
| 121 to 180 | Hard |
| More than 180 | Very hard |
Confirming it on city water
If a utility supplies your water, it publishes a yearly water quality report. Look for the line for total hardness, and note the units. Some reports give a range, or separate figures for groundwater and surface water, because hardness depends on the source feeding your area. If your report gives a range, ask the utility which source serves your address. If you cannot find the report, ask your water provider for it.
Confirming it on a private well
There is no report for a private well. EPA and CDC advise testing a well at least once a year with a certified laboratory, for safety items such as bacteria and nitrates. Ask the lab to include hardness, iron and manganese, which are the figures a softener decision turns on. Home test strips give a rough hardness reading and are useful for checking a softener is working; for sizing, a lab figure is better.
What to do with the figure
Compare your figure with the USGS grades. Soft or moderately hard water may not need a softener at all, and some utilities soften their water at the plant before it reaches you. Hard and very hard water are where a softener earns its place. Write the figure down, with its units and source, because any pro who sizes a softener for you needs it. If you already have a softener, test the water coming out of it with a strip from time to time: if it reads hard, the softener needs attention, and softener repair lists what to check.
Is hard water a health problem?
Utilities say no. They describe hard water as not a health hazard, and there is no health-based drinking water standard for hardness. The case for a softener is about scale, soap and appliances, not health.
Confirmed hard water and want a softener quote?
Once you have a figure, the sizing guide shows how it sets the size of a softener, and the whole house installation page covers the install.
Questions people ask
How can I tell if I have hard water?
Soap scum, poor lather, spots on glassware and scale on fixtures are the signs. To confirm it, read your utility’s yearly water quality report or test a well.
What level of hardness is hard water?
The USGS calls 121 to 180 mg/L hard and more than 180 mg/L very hard. That is about 7 to 10.5 grains per gallon for hard, and more for very hard.
