Two compartments in your dishwasher rarely get the attention they deserve: the salt reservoir and the rinse aid dispenser. Most households fill them on purchase -- or never fill them at all -- and leave the settings at whatever the delivery person configured. But using both correctly, with the right settings for your water hardness and usage, makes a genuine difference to how clean your dishes come out and how long the machine lasts.
This article covers the practical steps for both. For a deeper explanation of what dishwasher salt is and why it matters, see our article on what dishwasher salt is and whether you need it.
At National Appliance Repairs, our technicians regularly see the effects of salt and rinse aid misuse on dishwasher internals. Hard water scale on heating elements, blocked spray arm holes, and persistent cloudy glassware are almost all preventable with the right maintenance habits.
Part 1: Dishwasher Salt
What you'll need
- Dishwasher salt (available at any Australian supermarket in the cleaning products aisle)
- The funnel that came with your dishwasher (usually stored inside the machine)
- A cloth or paper towel
- Your dishwasher's manual (to confirm the location of the reservoir and any hardness settings)
Locating the salt reservoir
Remove the lower rack from the dishwasher. The salt reservoir is a round compartment in the floor of the machine, usually towards the front left or centre, with a screw-top cap -- often marked with an "S" icon or the word "salt". In some machines the indicator light on the control panel will tell you when the reservoir is low; in others you need to check manually.
Filling the reservoir
- Unscrew the cap counterclockwise and set it aside. Note that the reservoir is filled with water -- this is normal. The water is how the salt creates the brine solution used during regeneration.
- Place the funnel (included with most machines) into the opening. If you've lost the funnel, a small plastic kitchen funnel works. A steady hand and slow pouring also works for experienced users.Pour in the salt. Fill until you can see salt just below the top of the opening -- don't overfill. Most reservoirs hold approximately 1 to 1.5 kg. Some water will overflow as salt displaces it; this is normal.
- Wipe the threads around the reservoir opening before replacing the cap. Any salt sitting on the threads will corrode them over time, making the cap progressively harder to remove.
- Screw the cap back on firmly -- but do not overtighten it. It only needs to be hand-tight.
- Run a short cycle immediately before loading any dishes. Salt that has spilled into the machine's base can leave a salty residue on dishes in the next wash. A short rinse cycle flushes this away.
Setting the water hardness level
Most dishwashers with a built-in softener let you dial in your local water hardness, which tells the machine how often to run a regeneration cycle. Too low and the softener can't keep up -- scale forms. Too high and you're just burning through salt.
You'll find the setting either on a dial inside the salt reservoir compartment or somewhere in the digital menu. Check your manual if you're not sure where.
To set it right, you need your water hardness in milligrams per litre (mg/L) or degrees of hardness (°dH). Your water authority publishes this:
- SA Water for Adelaide
- Water Corporation for Perth
- Sydney Water for Sydney
- Melbourne Water for Melbourne
- Seqwater for south-east Queensland
Once you have the hardness figure, match it to the scale in your machine's manual and set accordingly. Most Adelaide and Perth households will need a mid-to-high hardness setting. Sydney and Melbourne households are typically at the lower end.
Water hardness reference guide for dishwasher settings:
| Water Hardness (mg/L as CaCO₃) | Approximate °dH | Setting Guidance |
|---|---|---|
| Below 60 mg/L | Below 3.4°dH | Soft water -- lowest setting; salt may barely be needed |
| 60--120 mg/L | 3.4--6.7°dH | Moderately hard -- mid setting; salt needed (most of Adelaide, Perth metro) |
| 120--180 mg/L | 6.7--10°dH | Hard water -- higher setting; frequent top-ups |
| Above 180 mg/L | Above 10°dH | Very hard -- highest setting; check monthly |
How often to top up
In most Australian households using the dishwasher daily:
- Soft water areas (Melbourne, Sydney): every two to three months
- Moderate hard water (Adelaide metro, Perth metro): monthly or close to it
- Hard water areas (some regional WA, regional QLD): potentially fortnightly
The indicator light, if your machine has one, is the most reliable guide. If the machine has no indicator, check the reservoir monthly as a starting habit and adjust frequency based on how quickly it empties.
Part 2: Rinse Aid
What rinse aid does
Rinse aid is a surfactant -- it reduces the surface tension of water, causing it to sheet off dishes and glassware in thin, even films rather than forming water droplets. Droplets dry and leave mineral spots; sheeting water evaporates cleanly. In hard water areas, where every drop of water carries dissolved minerals, this difference in drying behaviour has a large effect on the final appearance of glassware and cutlery.
Rinse aid also speeds up the drying cycle by promoting faster water runoff, reducing drying time and energy use.
Locating the rinse aid dispenser
The rinse aid dispenser is built into the inside of the dishwasher door, usually next to the detergent compartment. It has a small circular or rectangular cap, often marked with a wave or sun icon. Many machines have a small window in the cap that allows you to see the rinse aid level without opening it.
Filling the dispenser
- Open the dispenser cap -- it usually lifts or twists open rather than unscrewing.
- Pour rinse aid slowly into the opening. Most dispensers hold around 150--200ml. Fill until the level indicator (if present) shows full, or until rinse aid just reaches the base of the opening -- do not overfill.
- If any rinse aid spills onto the door or into the machine, wipe it up immediately. Spillage can cause excessive foaming during the next wash cycle.
- Close the cap firmly.
Setting the dosing level
The rinse aid dispenser has an adjustable dosing dial -- typically numbered 1 to 6, with higher numbers delivering more rinse aid per cycle. The correct setting depends on your water hardness:
- Soft water: setting 2--3
- Moderately hard water (most of Adelaide, Perth): setting 4--5
- Hard water: setting 5--6
If you see spots or cloudiness on glassware after washing, increase the dosing setting by one step and test over a few cycles. If you see rainbow streaks or a sticky film on dishes (over-dosing), reduce the setting by one step.
How often to refill
With daily dishwasher use and a mid-range dosing setting, the rinse aid dispenser typically needs refilling every four to eight weeks. The indicator window on the cap changes colour when the level is low; many machines also have an indicator light on the control panel.
Using Salt and Rinse Aid Together
Salt and rinse aid aren't interchangeable -- they do completely different things.
- Salt works at the start, softening the water before it hits the wash cycle. That reduces mineral load across the whole wash and protects the machine's internal components.
- Rinse aid works at the end, helping water sheet off dishes during the final rinse so they dry without spots.
In moderate-to-hard water, you need both. One without the other means either scale damage or spotty glasses.
Common Mistakes to Avoid
- Never put dishwasher salt in the detergent compartment. Salt is highly concentrated and can corrode the stainless steel interior if it sits directly in the wash water without being diluted through the softener system.
- Never use table salt as a substitute. Fine grain size, added iodine, and anti-caking agents make it unsuitable and potentially damaging to the softener resin.
- Never put rinse aid in the salt reservoir. They go in separate compartments for good reason.
- Don't skip the post-fill rinse cycle. Always run a short cycle after filling the salt reservoir to flush any spilled salt from the machine.
- Check both indicators monthly rather than waiting for problems to appear on your dishes.
FAQ
The salt indicator light is on even though I just filled the reservoir -- why?
The sensor measures brine concentration, not whether salt is present. After filling, the salt needs time to dissolve and build up a strong enough brine solution for the sensor to register. Run a cycle or two and the light should go off.
Do I need rinse aid if I use all-in-one tablets?
In soft water, the rinse aid in the tablet is usually enough. In moderately hard water -- which covers most of Adelaide, Perth, and parts of other capitals -- it often isn't, and you'll see spots and film on glassware. Fill the dispenser and set it to a lower dose.
My dishwasher manual asks for a hardness setting but I don't know my water hardness -- where do I find it?
Your local water authority publishes annual water quality reports online. Search "[your city] water hardness" or go directly to your supplier's website. SA Water, Sydney Water, Melbourne Water, Water Corporation (Perth), and Seqwater (South-East Queensland) all publish this data.
Can I leave the salt reservoir empty if I have a whole-house water softener?
If your softener is delivering genuinely soft water to all taps, the dishwasher may not need salt at all. Set the hardness to the lowest level and confirm with a water hardness test kit at the tap.
How long does a bag of dishwasher salt last?
A 2 kg bag at mid-level hardness with daily use lasts roughly two to four weeks in a hard water area like Adelaide, or two to three months somewhere with softer water. In hard water areas, buying in bulk makes more sense.
Conclusion
Using dishwasher salt and rinse aid correctly is a small investment of time and attention that pays back in cleaner dishes, better-looking glassware, and a longer-lasting dishwasher. Set the hardness level once based on your local water supply, develop a habit of checking the indicators monthly, and the rest takes care of itself.
If your dishwasher has developed a fault -- poor cleaning, blocked spray arms, a heating element failure from scale damage -- we at National Appliance Repairs repair dishwashers across Australia. Call 1300 434 380 for a fast, same-day assessment in most metro areas.
