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Comment by paulcole | Hacker News Reader

> So I would argue dishwashers are demonstrably more efficient than hand washing dishes

Yeah my argument is that this is nonsense. Just turn the tap off often when you’re scrubbing the dishes (use the water for rinsing) and it should be obvious that you’re using less water — particularly when you take into account the fact that a dishwasher uses 4 gallons of water no matter how many dishes are in it.

Under ideal conditions perhaps a modern dishwasher comes out ahead, but again maybe the ideal Rambo bird-killing-machine cat is also capable of decimating local bird populations.

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I have always, and I'm sure most people at home do, filled the dishwasher up completely before turning it on. That's quite a substantial load of dishes each time, 2 meals worth + sundry in a 5 person household. The dishwasher I have says it uses 6 litres per wash on the normal automatic mode. That's just over 1.5 gallons, and even if a total lie and it uses twice as much that's still only 12 litres / 3 gallons.

Where it probably falls down is where they have dishwashers in office kitchens where they don't fill it up and chuck it on anyway so they have their favourite coffee mug ready for the morning.

I've measured my (previously owned dishwasher; don't have one at the moment), and compared it to handwashing in terms of water used.

How did I measure it? I had the DW drain into a bucket.

The DW won hands down. I also learnt to wash dishes without the water running when I was a kid.

Yes, the proviso that you should only run it when it is full is important, but I assumed everyone knew that.

The other twist on water 'waste' is where does it go afterwards for recovery?

Cities often have systems, we're in rural Australia and are water conscious- as far as dish and clothes washing go that's grey water discharge which goes onto a near house mulch pit for household rottables and garden waste, the water that reaches the pit bottom hits a crushed stone bed with slotted pipe that drains water to above the vegetable garden and fruit trees (between the leach drains ) where it moves through the soil making tomatoes, potatoes, figs, oranges, lemons, grapefruit, etc.

No dishwasher, no tap running - but regardless of how much water we use in the kitchen none of that truly goes to waste, if we use more we just put less on the garden from the same source tanks (which are all level gauged).

Does that filter all the microplastics from washed clothes?

Microplastics shed from synthetic fibre clothes probably stay in the mulch, crushed rock and sand and don't reach the roots of the vegetables and trees and don't feature in the runoff (from sub surface water travel) at the base of the slope.

Mulch on garden with microplastics is likely ok as plants extract the minerals | elements they need.

I'd have to sample and check.

A great deal of our clothing, bedding, towels, etc is natural fibre in any case.

The average faucet puts out about 2 gallons per min. Even if i turn off the faucet between scrubbing it would take more than two mins of the faucet on for me. I do agree that it me use more dishes so there’s that.

You turn the faucet on at full blast every time you open it? I let out enough to rinse, but you do most of the mixing of soap and water for rinsing mechanically rather than just trying to blast it away with a high-pressure water stream.

Excellent point I don’t. But on the flip side I know I cannot use as little soap as a dishwasher since it’s down the drain

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