Your dishwasher is supposed to make life easier – load it up, press a button, and out come sparkling clean dishes. But what happens when plates come out still dirty, glasses look cloudy, or the entire top rack seems like it hasn't been touched? It's frustrating, especially when you're relying on your appliance to do the job properly.
The good news is that most cleaning problems have straightforward explanations and can be fixed. From blocked filters to spray arm issues, at Hoover, we will help you figure out why your dishwasher isn't performing as it should, and show you how to get it back on track.
Common causes of poor dishwasher cleaning
Understanding what causes dishwasher to not clean dishes is the first step towards solving the problem. Here are the most common culprits.
Blocked or dirty filter
The filter is one of the hardest-working parts of your dishwasher. It catches food particles and debris to prevent them from recirculating onto your clean dishes. Over time, however, this filter can become clogged with grease, food residue, and general muck.
When the filter is blocked, water can't flow properly through the dishwasher. This means dishes don't get the thorough spray they need, leaving them still dirty at the end of the cycle. A clogged filter is one of the most frequent answers to what causes dishwasher to not clean dishes, and thankfully it's easy to remedy.
Spray arm issues
The spray arms need to move freely and spray evenly to do their job. If the holes in the spray arms become blocked with limescale or food particles, water can't reach all your dishes.
Sometimes the spray arms can't rotate properly because items in the rack are blocking them. This is particularly problematic for the top rack, which relies on the upper spray arm. If you're wondering why your dishwasher doesn’t clean the top rack, a jammed or blocked spray arm is likely the answer. Tall plates, oversized pans, or awkwardly positioned containers can all prevent the spray arm from spinning freely.
Detergent or tablet problems
Even the best dishwasher can't clean properly without the right detergent. If your dishwasher tablet isn't dissolving fully, your dishes won't get clean. This can happen if the tablet dispenser is blocked, if you're using old or damp tablets, or if the water isn't hot enough to dissolve the detergent effectively.
The placement of your tablet matters too. Make sure it's going into the correct compartment and that nothing is blocking the dispenser door from opening during the cycle.
Hard water and limescale
If you live in a hard water area, limescale build-up can affect your dishwasher's performance. Limescale coats the heating element, reducing water temperature, and can also build up inside spray arms and on the interior surfaces of the machine.
Hard water is often why your glasses can come out of the dishwasher looking dirty. Even if the glasses are technically clean, limescale deposits leave them looking cloudy or streaky. Over time, this build-up affects the entire dishwasher's ability to clean effectively.
How to fix a dishwasher that isn't cleaning
Once you've identified the likely cause, fixing the problem is usually straightforward. Here's what you can do.
1. 1. Clean the filter and spray arms regularly
Remove the filter (usually found at the bottom of the dishwasher) and rinse it thoroughly under running water. Use a soft brush to remove stubborn debris. Take out the spray arms and clear any blocked holes with a toothpick or small brush.
2. 2. Check the water inlet and temperature settings
Make sure your dishwasher is receiving enough water and that it's hot enough. Most dishwashers need water at around 50-60°C to clean effectively. If your boiler thermostat is set too low, this could affect performance.
3. 3. Make sure detergent or tablet is placed correctly
Use fresh tablets and place them in the designated compartment, not loose in the bottom of the machine. Ensure nothing is blocking the dispenser from opening.
4. 4. Don't overload or block the spray arms
Load dishes thoughtfully, leaving space between items for water to circulate. Check that tall items aren't preventing the spray arms from rotating, and ensure the top rack isn't pushed back too far if that's where you're seeing cleaning issues.
5. 5. Run a dishwasher cleaner cycle
Use a dishwasher cleaning product to clear grease, limescale, and detergent residue from the interior. This deep clean can make a significant difference to performance.
Following these steps should address most problems with a dishwasher not cleaning properly. Regular maintenance prevents problems from developing in the first place.
How to clean a dishwasher that is not cleaning properly
If your dishwasher itself needs a thorough clean to restore its performance, follow these steps:
1. 1. Remove and rinse the filter
Take out the filter from the base of the dishwasher and rinse it under hot running water. Use a soft brush or old toothbrush to scrub away any stubborn residue. Check the filter housing area for any debris that might have accumulated.
2. 2. Clean spray arms and ensure holes aren't blocked
Remove both the upper and lower spray arms by twisting or unclipping them (check your manual if you're unsure how). Hold them under running water and use a toothpick or thin wire to clear any blocked spray holes. Rinse thoroughly before reattaching.
3. 3. Wipe seals and interior walls
Use a damp cloth to wipe around the door seals, where grime and mould can build up. Clean the interior walls and door, paying attention to corners and edges where food particles can gather.
4. 4. Run a cleaning cycle with dishwasher cleaner or vinegar
Place a dishwasher cleaning tablet or a cup of white vinegar on the top rack and run a hot, empty cycle. This will help dissolve limescale, grease, and detergent build-up throughout the system.
This process should be done every month or two to keep your appliance running efficiently.
When to call for professional help with a dishwasher
While many cleaning issues can be resolved at home, some situations call for expert attention.
If your dishwasher makes unusual noises alongside poor cleaning performance, there could be a mechanical issue with the pump or motor. Similarly, if dishes remain dirty despite regular maintenance and all the fixes suggested above, an internal component could have failed.
Water not draining properly or not heating up are signs of more serious problems that typically need professional repair. A qualified engineer can diagnose issues with heating elements, pumps, or electronic controls that aren't accessible or safe to fix yourself.
Choosing a reliable dishwasher
If your dishwasher is beyond repair or you're simply ready for an upgrade, modern appliances offer features that help prevent cleaning problems.
Hoover dishwashers are designed for efficiency and reliability, with multiple wash programmes to suit different loads and levels of soiling. Self-cleaning functions and effective filtration systems reduce the build-up that can affect performance over time. Adjustable racks and thoughtfully designed interiors make it easier to load dishes properly, ensuring water reaches everything that needs cleaning.
A dependable dishwasher that's easy to maintain means fewer frustrations and more consistently clean dishes. Explore Hoover's range of dishwashers to enjoy sparkling clean dishes for years to come.