Dishwasher not cleaning dishes properly (all brands)
✅ Safe to check yourself
This is a common, low-risk check most people can do safely. Always unplug the appliance (or isolate power) before touching internal parts.
Quick TipTake a photo of the appliance's model/serial number sticker now — you'll want it if this does end up needing a part or an engineer.
Dishes coming out with food residue, cloudy glasses, or a greasy film almost always trace back to loading, blocked spray arms, or detergent — not a mechanical fault — and is one of the most fixable dishwasher complaints there is.
What to check first
- Remove both spray arms (they usually just lift or unclip) and hold them up to the light — check every small hole around their length isn’t blocked with limescale or food debris, and rinse them under a tap.
- Check nothing large is blocking the spray arms from spinning freely — a stray utensil or oversized item is a very common cause of “some dishes clean, some don’t”.
- Check you’re not overloading or blocking items from each other — plates and bowls need to face the centre of the spray pattern, not stack flat or nest inside one another.
- Check your detergent isn’t old/clumped (tablets absorb moisture over time and stop dissolving properly) and that the dispenser flap opens and closes freely.
- Run a hot maintenance/cleaning cycle empty, ideally with a dedicated dishwasher cleaner, to clear grease and limescale build-up from the whole system.
When to call an engineer
If spray arms are clear, loading is correct, and detergent is fresh but cleaning is still poor, the wash pump or heating element (needed to reach an effective wash temperature) may be underperforming — worth a professional check.