In a hard water home, dishwasher detergent mistakes such as using hand dish soap, dosing as if the water were soft and starting the cycle with cold water leave film, spots and sometimes a kitchen floor full of suds. Fresh automatic dishwasher detergent, hot water run at the sink first, and powder or gel doses adjusted for hard water address all three.
Mistakes at a glance
| Habit | What it leads to | Do this instead |
|---|---|---|
| Using hand dish soap when the detergent runs out | Thick foam that can spill out through the door | Use automatic dishwasher detergent only |
| Using the same powder or gel dose as in a soft water area | Film and spots from hardness minerals | Hard water generally needs more powder or gel; follow the label |
| Starting the dishwasher with cold water in the line | Detergent that doesn't dissolve and activate well | Run the nearest hot faucet until the water is hot |
| Storing an open box under a damp sink | Clumped, weak detergent | Keep it tightly closed in a cool, dry place |
| Adding detergent hours before running | Detergent that cakes in the cup | Add it just before you start |
| Spilling rinse aid and leaving it | Foam that can overflow | Wipe up spills before running |
| Treating hard water as only a cosmetic issue | Mineral deposits that can damage the dishwasher | Consider softening, and keep rinse aid filled |
The ones that matter most
Hand dish soap in the dishwasher
Hand dish soap is made to foam, and a dishwasher sprays water hard enough to turn a squirt of it into a tub full of suds. Maytag's troubleshooting page, linked below, says not to use hand soap or laundry detergent in a dishwasher, lists too much or the wrong detergent among the causes of oversudsing, and notes that spilled rinse aid can cause foam and lead to overflowing. If it happens, stop the cycle and follow your manual's steps for clearing suds.
Dosing as if the water were soft
For homes on the San Antonio Water System, the water is hard. SAWS says the typical hardness of the water it provides ranges from 15 to 20 grains per gallon, from calcium carbonate that occurs naturally in water from the Edwards and Trinity aquifers. Maytag's oversudsing page says heavy soil and hard water generally require extra detergent, that soft water needs less powder or gel, and never to use less than one tablespoon per load. Pods are pre-measured, so with pods the fixes are hot water, fresh detergent and rinse aid rather than a bigger dose.
Ignoring what 15 grains means
Whirlpool sets a specific line. Its guide to getting the best results from a dishwasher says extremely hard water, at 15 grains per U.S. gallon or more, can leave mineral deposits that damage your dishwasher, and recommends a water softener. SAWS's typical range starts at that line. Whirlpool also says rinse aid can improve drying and reduce water spots and filming, which matters more in water this hard.
Cold water and stale detergent
Whirlpool says to run the hot water faucet nearest the dishwasher until the water is hot, because hot water dissolves and activates the detergent. It also says to add detergent just before starting, use fresh detergent, and store it tightly closed in a cool, dry place. A box that has absorbed moisture under the sink can clump and clean poorly. Loading habits that keep detergent from reaching dishes are covered in dishwasher loading mistakes that lead to dirty dishes.
Signs it's already caused a problem
- A white or cloudy film on glasses that doesn't wipe off
- Gritty, chalky buildup on the door, the tub or the spray arms
- Suds left in the tub or foam at the door seal
- Detergent left caked in the dispenser after a cycle
- Dishes that come out wet or spotty even with rinse aid filled
- Water that stays in the bottom of the tub after the cycle
If film or buildup comes back quickly after you change your habits, mineral scale may be affecting the spray arms, heater or pump, and a dishwasher check can confirm it.
Sources
- San Antonio Water System: Water Quality FAQs
- Whirlpool: Getting the Best Results when Using a Dishwasher
- Maytag: Oversudsing or Residue on Dishes
Habit to keep: Keep the rinse aid dispenser filled, since hard water makes spots and film more likely.
When hard water buildup keeps coming back no matter what you change, ProFix San Antonio can check the dishwasher at (210) 761-6006.