Much of the water that comes out of San Diego County taps travels a long way to get here, from the Colorado River and from Northern California, and it arrives carrying a lot of dissolved calcium and magnesium. The water is safe to drink, but it's hard, and hard water leaves mineral scale behind wherever it's heated or evaporates. Inside appliances that means narrowed valves, clogged screens, cloudy glassware and heating elements wearing a crust that makes them work harder.
The U.S. Geological Survey classes water as hard starting around 121 mg/L of hardness as calcium carbonate. Rather than worrying about the exact number at your address, it's more useful to know the signs and where to look.
Symptom-to-fix checklist
| What you notice | Where the scale is | What to try |
|---|---|---|
| White, chalky film on glasses and dishes | Dishwasher tub, spray arms, and the dishes themselves | Fill the rinse-aid dispenser, use detergent suited to hard water, and run an empty cycle with a dishwasher cleaner or a cup of white vinegar set upright on the top rack |
| Dishwasher fills slowly or shows a fill error | The small screen at the water inlet valve | Turn off water and power, then have the inlet screen checked and cleaned; a scaled valve may need replacing |
| Spray arms leave spots unwashed | Clogged spray arm holes | Remove the arms and clear each hole with a toothpick, then rinse |
| Ice cubes small, hollow or slow to form | Ice maker fill tube, inlet valve, refrigerator water filter | Replace the filter on schedule and check the fill tube for ice or mineral buildup |
| Water dispenser slow or sputtering | Water filter or inlet valve | Install a fresh filter and flush several gallons through the dispenser |
| Washer takes a long time to fill | Inlet hose screens at the back of the washer | Shut both valves, remove the hoses, and rinse or gently brush the small screens |
| White crust in the washer dispenser drawer | Detergent and softener channels | Remove the drawer and soak it in warm water with vinegar, then scrub |
| Stiff, dull towels | Mineral residue in fabric | Use the correct dose of detergent; more detergent in hard water can leave more residue, not less |
Dishwashers take the worst of it
A dishwasher heats water and then lets it dry on every surface, which is exactly the condition that leaves scale. Over time the heating element gets coated, the inlet valve screen narrows, and the tub develops a white haze that no detergent removes. Rinse aid is worth using in hard-water areas; it helps water sheet off instead of beading and leaving spots. If your dishwasher has a built-in water softener, which some European models do, set its hardness level according to the manual and keep its salt reservoir filled with dishwasher salt.
Before using any acidic cleaner, check your dishwasher manual. Some manufacturers prefer their own descaling product.
Ice makers and water filters
The refrigerator's water filter catches some minerals and protects the ice maker valve, but only if it's replaced on time, typically every six months. A neglected filter slows water flow, which leads to small cubes and a sluggish dispenser. Scale can also build up where the fill tube enters the ice maker. Our monthly ice maker routine walks through the cleaning.
A schedule that works for hard water
- Every week: keep the rinse-aid dispenser full.
- Every month: clean the dishwasher filter and run an empty cleaning cycle.
- Every three months: pull the spray arms and clear the holes; soak the washer dispenser drawer.
- Every six months: replace the refrigerator water filter and check the washer inlet screens.
- Yearly: inspect washer hoses and the dishwasher inlet connection for crust or seepage.
What about a whole-house softener?
A water softener removes much of the hardness before it reaches any appliance and many homeowners find it worthwhile. It's a plumbing decision with its own maintenance and costs, so it's worth getting advice from a plumber or water treatment specialist. Even with a softener, keep up with filters and the dishwasher filter.
When descaling isn't enough
Scale that has built up for years can ruin an inlet valve or a heating element. If the dishwasher still won't fill properly, won't heat, or shows an error code after cleaning, book a dishwasher repair visit. For brands with complex filter systems, like Bosch, the filter assembly is especially important to keep clean. An ice maker that stops producing despite a new filter is a job for our ice maker technicians.
Start with the table above, though. Most hard-water complaints we see improve a lot with nothing more than a clean filter, rinse aid and a descaling cycle.