If you live in Adelaide, Perth, parts of Queensland, or many regional areas of Australia, you're likely dealing with hard water. That white chalky buildup on your taps, the residue on your shower screens, and those stubborn spots on your glassware are all calling cards of hard water. For dishwasher owners, hard water presents specific challenges that can affect cleaning performance, leave unsightly deposits on dishes, and even shorten your appliance's lifespan. This comprehensive guide addresses these issues with practical solutions.
Key Takeaway
Hard water doesn't mean you can't have sparkling dishes. With the right combination of dishwasher salt, rinse aid, appropriate detergent, and regular maintenance, you can achieve excellent results even in the hardest water areas of Australia.
Understanding Hard Water
Hard water contains high concentrations of dissolved minerals, primarily calcium and magnesium. These minerals are picked up as water travels through limestone, chalk, and other mineral-rich geological formations. Water hardness is measured in parts per million (ppm) or milligrams per litre (mg/L) of calcium carbonate.
Australian Water Hardness Levels
Water hardness varies significantly across Australia:
- Adelaide: Notoriously hard water, ranging from 200-350 ppm depending on the suburb
- Perth: Generally moderate to hard, 100-200 ppm for most suburbs
- Brisbane: Typically soft to moderate, 50-100 ppm
- Sydney: Generally soft, 40-80 ppm
- Melbourne: Soft water, typically under 50 ppm
- Regional areas: Highly variable, especially those using bore water
Water below 60 ppm is considered soft; 60-120 ppm is moderately hard; 120-180 ppm is hard; and above 180 ppm is very hard. Many Adelaide suburbs exceed 300 ppm, placing them among the hardest municipal water supplies in Australia.
How Hard Water Affects Your Dishwasher
Hard water creates several problems for dishwasher operation and the dishes you wash.
Limescale Buildup
When hard water is heated, dissolved minerals precipitate out and form limescale, that hard white or greyish deposit you see on heating elements, spray arms, and interior surfaces. Over time, limescale can clog spray arm holes, reducing water pressure and coverage. It insulates heating elements, making them work harder and use more energy. It can even interfere with door seals, causing leaks.
Spots and Film on Dishes
The most visible symptom of hard water is the white spots or cloudy film that appears on glasses, cutlery, and dark dishes. This residue is mineral deposit left behind as water evaporates. It's particularly noticeable on glassware and stainless steel.
Reduced Cleaning Effectiveness
Hard water minerals interfere with detergent performance. The minerals bind with surfactants in detergent, reducing their ability to lift away grease and food particles. You may notice that dishes don't come out as clean as expected, even when using quality detergent.
Check Your Dishwasher's Interior
Open your dishwasher and look at the interior walls, spray arms, and around the door seal. If you see white deposits or a hazy film, you have hard water buildup that needs addressing.
Solution 1: Use Dishwasher Salt
Most European-brand dishwashers (Bosch, Miele, Siemens, etc.) have a built-in water softening system that requires regular addition of dishwasher salt. This is your primary defence against hard water.
How It Works
The dishwasher's water softening system uses an ion exchange process. Hard water passes through resin beads that swap calcium and magnesium ions for sodium ions, effectively softening the water before it's used for washing. The salt regenerates the resin beads, keeping the system effective.
Using Salt Correctly
The salt reservoir is typically at the bottom of your dishwasher, with a screw-on cap. Fill it with dishwasher salt (not table salt, which contains additives that can damage the system) until the reservoir is full. Your dishwasher will have a light or indicator showing when salt needs to be refilled, but in hard water areas, you may need to refill more frequently than the indicator suggests.
Adjusting Water Hardness Settings
Most dishwashers with salt systems allow you to program your water hardness level. Consult your user manual for instructions. Setting this correctly ensures the softening system regenerates at the right frequency. Your water authority's website typically provides hardness data for your area.
Note for Some Dishwashers
Some Australian-market dishwashers don't have salt reservoirs. If yours doesn't, you'll need to rely more heavily on other solutions like rinse aid and specialty detergents. Check your user manual to confirm whether your model has this feature.
Solution 2: Always Use Rinse Aid
Rinse aid is essential in hard water areas, not optional. It reduces water's surface tension, helping it sheet off dishes rather than forming droplets that leave mineral deposits as they dry.
Fill the Dispenser
Keep your rinse aid dispenser filled. Most dishwashers have an indicator that shows when it's running low. In very hard water, you may need to adjust the dispenser to its highest setting. Experiment to find the right level: if you still see spots, increase it; if dishes have a slight smeary film, decrease it.
Choosing Rinse Aid
Standard rinse aids work well for most situations. Some brands offer formulations specifically designed for hard water areas. While premium options exist, basic rinse aid is usually sufficient when used consistently.
Solution 3: Choose Appropriate Detergent
Your detergent choice matters significantly in hard water areas.
Tablet Selection
Look for tablets specifically formulated for hard water or those that include water softening agents. Premium tablets generally perform better in challenging water conditions. Some tablets include extra rinse aid and salt, helpful if your dishwasher lacks these features.
Using More Detergent
In hard water, you often need more detergent than the package suggests. If you're using powder or gel, consider increasing the amount by 25-50% compared to soft water recommendations. Don't overdo it, as excess detergent can leave its own residue.
Solution 4: Regular Descaling
Even with proper salt and rinse aid use, limescale will build up over time. Regular descaling is essential maintenance in hard water areas.
Monthly Treatment
Run an empty cycle with a dishwasher cleaner or descaler monthly. These products dissolve limescale and remove buildup from the interior, spray arms, and drain system. Follow the product instructions carefully.
Vinegar Alternative
White vinegar is a natural descaler. Place a cup of vinegar in a dishwasher-safe container on the top rack and run a hot cycle. While not as powerful as commercial descalers, regular vinegar treatments help control buildup between deeper cleans.
Spray Arm Maintenance
Periodically remove your spray arms and soak them in vinegar solution to dissolve any mineral deposits blocking the spray holes. Use a toothpick to clear any visible blockages. This maintains water pressure and coverage.
Solution 5: Consider Water Treatment
For households with very hard water facing persistent issues, whole-house water treatment offers a more comprehensive solution.
Water Softening Systems
A whole-house water softener treats all water entering your home, benefiting not just your dishwasher but also your water heater, washing machine, showers, and taps. These systems require professional installation and ongoing maintenance, including regular salt additions. The upfront and ongoing costs are significant but may be worthwhile in very hard water areas where appliance damage and replacement costs add up.
Under-Sink Filters
Some under-sink filter systems can reduce water hardness specifically for your kitchen. These are less expensive than whole-house systems but only treat water at that point of use.
Long-Term Benefits
Addressing hard water protects not just your dishwasher but all water-using appliances in your home. Water heaters, in particular, suffer significant efficiency losses from limescale buildup.
Fixing Existing Problems
Cloudy Glasses
If your glasses already have a cloudy film, try soaking them in white vinegar for 15-30 minutes. If the cloudiness wipes away, it's mineral deposit that you can remove. Wash normally after treating. If the cloudiness remains, the glass may be etched (permanent damage from soft water and too much detergent) and cannot be repaired.
Spotted Cutlery
For stainless steel cutlery with water spots, a paste of bicarbonate of soda and water applied with a soft cloth can remove deposits. Rinse and dry immediately. Prevent future spots by increasing rinse aid and ensuring the dishwasher is using appropriately softened water.
Heavily Scaled Dishwasher
For a dishwasher with significant limescale buildup, you may need multiple descaling treatments. Run a heavy-duty cycle with a commercial descaler, wait until complete, then repeat. Clean spray arms manually as described above. Once cleared, maintain with monthly treatment.
Prevention Checklist
- Know your water hardness level and set your dishwasher accordingly
- Keep the salt reservoir filled and check it regularly
- Use rinse aid and adjust the dispenser for your conditions
- Choose detergent appropriate for hard water
- Run a descaling cycle monthly
- Periodically inspect and clean spray arms
- Wipe door seals to prevent mineral buildup
Living with hard water requires a bit more attention to your dishwasher, but with the right approach, you can achieve spotless dishes and protect your appliance for years of reliable service.