I've been using the same brand of dishwasher tablets for months, but lately everything comes out with this chalky white film on it. I've tried running a rinse cycle and even checked the salt levels, but nothing seems to help. Is this a water hardness issue or something wrong with my machine?
The white stuff is almost definitely mineral deposits, and here's something that might be getting overlooked - your rinse aid dispenser could be empty or set too low. Rinse aid is basically designed to fight exactly this problem by helping water sheet off instead of leaving spots and film. If you're running low on it or haven't refilled it in a while, that's a quick fix to try first before diving into deeper troubleshooting.
If the rinse aid is topped up and you're still seeing the residue, then you're probably dealing with a combination of hard water and detergent buildup in the machine itself. The previous answer about the spray arms and filter is spot on - those definitely get gunked up. But also run your dishwasher empty with a cup of white vinegar on the top rack to descale the whole interior. Do this maybe once a month if you've got really hard water. Some people swear by commercial dishwasher cleaners too, but vinegar works and costs basically nothing.
One last thing worth checking - some detergents perform worse in hard water than others. If you've been using the same tablets for months and the problem just started recently, it might be worth switching brands to see if a different formula works better for your water. That's kind of a band-aid solution, but combined with the rinse aid and a good cleaning of the machine, it should clear things up.
Clean out your dishwasher's spray arms and filter - they get clogged with mineral buildup and detergent residue, which stops water from rinsing properly. If that doesn't work, you've likely got hard water that's overwhelming your rinse aid, so bump up the rinse aid setting and consider adding a water softener tablet to each load.
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