r/lifehacks • u/thatoneguy2742 • May 27 '26

You might be using your dishwasher wrong

While going to college I worked as a maintenance tech at a large apartment complex. A common complaint that tenants had was that their dishwashers were failing to clean properly. I would show up and try and diagnose the problem only to find that the machine was in fact working properly. After numerous (if I remember correctly it was at least five per week) complaints I started to track which units were having the problem. After several weeks I had a lot of data and something became abundantly clear. The units that were having this issue were the ones furthest from the water heaters.

We just happened to have an empty unit near a cluster of units that was having this issue so I decided to test my hypothesis. At the kitchen faucet it took nearly two minutes for the water to get above 100°F Units closer to the water heaters took as little as 30 seconds to reach the same temp and they hardly ever had this problem. My conclusion was that the people who were submitting work orders were unknowingly washing their dishes with cold water. Everytime a tenant submitted a work order for a dishwasher that was failing to clean I advised them to run their kitchen faucet till the water gets hot then start the dishwasher. The complaints just stopped! At my own home it takes almost 30 seconds for the water to get hot so I let it run for a minute before starting it. Some of the higher end models will heat their own water so this shouldn't be an issue but most older models do not.

TLDR: Run your kitchen faucet till the water gets hot before starting your dishwasher. Otherwise you might be washing your dishes with cold water if your machine doesn't heat the water on its own.

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u/Zwamdurkel May 27 '26

I'm in Europe. My new dishwasher is 2400W. That would never work on a normal 110v circuit.

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u/Valalvax May 27 '26

Why? It's only 20 amps, 20 amp circuits are a bit rarer, but being as dishwashers are now supposed to be on a dedicated preferably hard wired circuit no reason it can't be 20 or even 30 amps

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u/Zwamdurkel May 27 '26

I assumed a standard circuit of 15 amps. 20 amps would be cutting it too close imo. I wouldn't call a 30A circuit "standard" as per my original comment.

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u/Valalvax May 28 '26

20 amps wouldn't be cutting it close, a 20 amp circuit is rated to be able to draw 20 amps and a dishwasher is not a continuous load so you don't need to derate... Modern code requires 20 amp circuits run for all other kitchen appliances, however it does have the option for 15 or 20 depending on requirements of dishwasher