How to Prevent a Dishwasher from Leaving Spots on Glasses
Cloudy or spotted glasses after the dishwasher are one of the most common complaints from dishwasher owners — and the good news is it's almost always fixable. The spots aren't usually a sign of a faulty dishwasher. They're caused by a combination of hard water, rinse aid levels, and detergent choice. Here's how to fix it.
Why Glasses Come Out Spotty
Water spots on glasses are typically caused by one of two things:
- Hard water: Sydney's water is moderately hard, containing dissolved calcium and magnesium minerals. When water droplets evaporate during the drying cycle, these minerals are left behind as white spots or a hazy film.
- Insufficient rinse aid: Rinse aid breaks the surface tension of water, causing it to sheet off dishes rather than form droplets. Without enough rinse aid, droplets dry in place and leave mineral deposits.
Step 1: Check Your Rinse Aid Level
The rinse aid dispenser in your dishwasher (usually located inside the door, next to the detergent dispenser) has a small indicator window that shows when it's low. Keeping this topped up is the single most effective fix for spotty glasses.
Even if the dispenser isn't empty, check the dispenser setting — most dishwashers have an adjustable rinse aid dosage setting (usually a dial inside the dispenser cap, numbered 1–6 or similar). Try increasing the setting by one or two levels and run a few cycles to see if it helps.
Step 2: Use a Quality Rinse Aid
Not all rinse aids are equally effective. Generic or store-brand rinse aids can be less concentrated and require higher settings to work properly. Finish Rinse Aid and similar quality brands are well-regarded and effective at typical settings.
Step 3: Check Your Water Softener Setting
Many dishwashers (particularly European brands like Bosch and Miele) have a built-in water softener that can be set to match your local water hardness. If yours has this feature, check the manual for the recommended setting for your water supply.
Sydney Water's water hardness is approximately 60–100 mg/L (varies by area), which is classified as moderately hard. This is worth entering accurately in your dishwasher's settings if the option exists.
Step 4: Use a Combined Detergent Tablet with Rinse Aid
If you're using basic powder detergent, switching to an all-in-one tablet that includes rinse aid can help. However, all-in-one tablets may not perform as well as using detergent and separate rinse aid, particularly in hard water areas.
Step 5: Run the Eco Cycle Less Often
Eco cycles use lower temperatures and less water, which can be less effective at fully rinsing detergent and minerals. If you consistently use eco mode and have persistent spotting, try a standard or intensive cycle to see if results improve.
Step 6: Try a Dishwasher Cleaner
Mineral buildup inside the dishwasher itself — on the spray arms, inside the pump, and on the door seal — can contribute to poor performance. A monthly dishwasher cleaning tablet or citric acid cycle (run an empty dishwasher on hot with a cup of citric acid powder in the base) can help remove buildup.
What If the Glasses Are Permanently Clouded?
If glasses have been etched rather than spotted, the damage is likely permanent. Etching is a chemical attack on the glass surface caused by over-dosing with detergent, too-high temperatures, and low mineral content (soft water). Unlike mineral spots, etching is irreversible.
To prevent etching: use the correct amount of detergent, don't use the hottest cycle for delicate glassware, and consider a dishwasher that has a specific glassware protection setting.
Browse Our Dishwasher Range
Oceania Appliances stocks a wide range of dishwashers with adjustable water softeners, variable rinse aid dosing, and dedicated glasscare programmes. Visit our Wetherill Park showroom at 2/14 Centre Place, open 7 days, 10 am to 8 pm.