Dishwasher uses less water than washing by hand

It may seem hard to believe, but handwashing your dishes uses more water than a dishwasher.

Dishwasher vs handwashing

In 2011, a study done at the University of Bonn, in Germany, found households without a dishwasher used on average more than twice as much water to clean dishes as those with one.

Since then, dishwasher design has advanced, making improvements in energy and water efficiency.

I was interested to see how my water use rated when handwashing dishes, compared to the study. Consumer testing shows the average dishwasher uses 13L to clean a full load. In comparison, my kitchen sink at two-thirds full holds 13L. To wash as many dishes as a full dishwasher, I’d need to run at least three sink-loads (39L), including pre-rinsing. Then, if I rinsed the suds off my plates, that’s another sink-load. It’d be even more if I rinsed under a running tap (which uses about 6L per minute).

My home trial found I will save water by using the dishwasher, but there are many variations to handwashing, so it’s important to think about how many litres or sinks of water you use.

Ways to save water using a dishwasher

There are steps you can take to help your dishwasher conserve even more water.

• Skip the rinse: Rinsing your dishes before putting them in the
  dishwasher isn’t necessary (though remove food scraps from heavily
  soiled dishes). The only time you should rinse items before putting
  them in the dishwasher is if you don’t turn it on every day and want
  to prevent dishes stinking up the machine between washes. If you do
  pre-rinse dishes, save water by using the dishwasher’s rinse-only
  cycle and then fast wash.

• Wash a full load: A full load is the most efficient way of washing
  your dishes – but don’t overload your dishwasher. A half-load cycle
  can be useful, as it only washes half the machine (usually the top
  rack), but make sure to follow the manufacturer’s guidelines on how
  to stack the dishes.

• Efficient loading: Heavily soiled dishes placed high in the
  dishwasher can dirty lower ones and poorly stacked items can block
  spray arms, which can prevent water and detergent from reaching all
  the dishes. Put heavily soiled items, such as pots and pans, in the
  bottom. Plates and cutlery baskets are best placed in the bottom
  rack. Cups, glasses and bowls are better off in the top rack, as are
  plastic items (to avoid warping).
  
  See our How to stack your dishwasher article for more advice.

• Autosensing and eco mode: Autosensing is a reliable method of saving
  water for most dishwashers, as it automatically adjusts the water and
  temperature based on the dirtiness of the dishes. Eco mode also uses
  less water and energy, but takes longer and may be a less intense
  wash.

• Choose a water-efficient model: When buying a new dishwasher, compare
  water star ratings of similar capacity models. It shows how
  water-efficient a dishwasher is at a glance – the more stars, the
  more efficient.