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How much water does a dishwasher use? The definitive guide

Worried your dishwasher is denting your eco-friendly credentials? We’ve got good news for you.

Updated

An open, loaded dishwasher

How much water does a dishwasher use? Do dishwashers save water compared to washing dishes by hand? These are the inevitable questions for the environmentally conscious among us (who still want the convenience a dishwasher brings).

It certainly sounds like a lot of water when you hear it sloshing about during a cycle. But you’ll be pleased to know dishwashers don’t use as much water or energy as you might think – as long as they’re used efficiently.

To help you do your bit for the planet and save water around your home, we’ve put together this definitive guide to dishwashers vs. hand washing, with eco-friendly tips for both.

Dishwasher vs hand washing: which is better for the environment?

Let’s face it, this is what we all want to know. Dishwashers are convenient time savers, but do they save water and energy or waste it? Here’s everything you need to know about using the dishwasher vs. hand washing.

Do dishwashers use less water than washing up by hand?

The short answer to this is yes (usually). According to a leading manufacturer, a standard dishwasher uses around 9.5 litres of water per wash, while hand washing generally uses up to 60 litres. That’s a big difference.

A bit of maths will tell you using the dishwasher can save a whopping 85 per cent of water compared to washing dishes by hand. And switching from hand washing to a dishwasher can save up to 18,000 litres of water per year.

There are a few things to bear in mind here. First, dishwasher water usage varies depending on how old your machine is – older models are likely to be more wasteful. Second, the amount of water you use while hand washing will vary greatly depending on how you choose to hand wash – from keeping the tap running to filling a washing up bowl. (Scroll down for our tips on eco-friendly hand washing.)

Are dishwashers more energy efficient than hand washing?

When it comes to energy efficiency, dishwashers also come out on top. A recent study by the School for Environment and Sustainability at the University of Michigan found that hand washing dishes produces double the amount of greenhouse gases over a 10-year period compared to using a dishwasher. (The greenhouse gases associated with hand washing dishes mostly come from the energy it takes to heat the water, so it does depend on your heating system.)

The caveat here is the same as for water usage – newer dishwashers are considerably more energy efficient than older models.

Which cleans better – the dishwasher or washing by hand?

Even on an eco setting, most dishwashers wash dishes at around 50ºc or more. That’s far hotter than water your hands could handle. Combine this with a great dishwasher detergent and the dishwasher is the clear winner here (as long as you load it properly).

How much does it cost to run a dishwasher every day vs. hand washing dishes?

The biggest cost of using a dishwasher is how much it adds to your energy and (possibly) water bills. We’ve already seen that dishwashers are usually more energy and water efficient than hand washing, so it’s safe to say that over the long term they’re more cost effective too.

That said, it’s super important to bear in mind that energy efficiency (and therefore running costs) depends on model. The Energy Saving Trust estimates dishwashers typically cost between £37 and £48 a year to run.

The most efficient dishwashers on the market have an A+++ rating and cost around £7 less to run per year than the lowest rated dishwashers that you can buy of the same size (and they use less water too).

Is hand washing ever the better choice?

The dishwasher has come up trumps so far, but let’s not forget some items aren’t dishwasher safe – it’s not time to hang up those rubber gloves just yet.

Most cookware, crockery and cutlery you buy these days will be dishwasher safe and they’ll likely have the dishwasher symbol on them (or on their packaging) to indicate as much. But make sure you check with the manufacturer of your dishwasher if you're unclear about anything.

As a general guide, things that are unsuitable for a dishwasher include:

  • certain types of plastic: always look out for dishwasher symbol on plastic items
  • cast iron pans: if these are uncoated, they will rust
  • antique china: the hot water could cause them to fade
  • sharp knives: your knives will dull quicker in the dishwasher, so it’s still best to hand wash them
  • wooden spoons: the wood will swell in the dishwasher and eventually crack
  • aluminium pans: these react with the detergent solution and eventually discolour.

7 clever ways to cut down your dishwasher water usage and boost energy efficiency

So we now know the dishwasher is generally more eco-friendly than hand washing, but we’ll most likely need to do both at least occasionally.

Our tips for eco-friendly dishwashing will help you save water and energy, whether you’re hand washing or using a dishwasher.

1. Choose or switch to a more energy-efficient model

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An A+ energy rating sign on the door of a dishwasher

The European Commission estimates that switching to a more energy efficient dishwasher can save you up to €300 (about £270) over the average lifetime of the machine.

There are tips on choosing the right dishwasher further on in this guide, but the key thing to look out for is the energy label. Dishwashers are labelled on an energy efficiency scale ranging from A+++ (most efficient) to D (least efficient). Aim to get A+ or better if you can.

2. Make sure the dishwasher’s fully loaded

An open, loaded dishwasher

According to the Energy Saving Trust, cutting just one dishwasher cycle a week by making sure it’s always full before it’s turned on can save £9 on your electricity bill, and save water to boot.

And while we’re speaking about loading the dishwasher, make sure it’s loaded correctly – otherwise, you’ll end up re-washing your dishes (and using more water).

3. Whatever you do, don’t pre-rinse

Pre-rinsing dishes before they go in the dishwasher could be wasting more than 22,000 litres of water per year. That’s a lot of water.

You might think the dishwasher can’t handle that baked-on crust or dried-up sauce (yuck). But the truth is, any modern dishwasher worth its salt absolutely can. Just make sure you scrape off obvious food remnants and use an effective dishwasher tablet or detergent – the machine will do the rest.

4. Use the economy or energy-save program

Dishwasher label showing eco energy-saving setting

The clue is in the name with this nifty feature. Eco or energy-save settings are, unsurprisingly, the most efficient in terms of energy and water usage.

Dishes are washed at a lower temperature, typically 50ºc, and the programs use around three litres less water than the standard dishwasher cycle. Some dishwashers also have a low water or quick wash cycle – worth looking out for if there isn’t an economy program on yours.

5. Don’t be drawn in by the half-load setting

You might be thinking half-load equals half the dishwasher water usage. Unfortunately, that’s not the case. While this type of program does use less water and energy than a normal cycle, the water saving doesn’t equate to half.

It's always more economical to wait until your dishwasher is completely full and then select an economy or water-saving cycle.

6. Air dry your dishes

Instead of letting your dishwasher use electric heat or a fan to dry the dishes, just open the door at the end of the washing cycle and let them air dry. Researchers found that cutting heated drying from your dishwasher routine decreases its greenhouse gas emissions by 11 per cent. Not bad.

7. Keep your dishwasher in good condition

If you want your dishwasher operating at full efficiency, it’s important to keep it in tip top condition. They may be boring, but reading the instructions and guides that come with your machine will help you understand what basic maintenance is needed. You can also check out our top tips for cleaning your dishwasher.

The most eco-friendly way to wash dishes by hand

A basin containing dishes in a sink, alongside a basin containing water

Using a washing up bowl is the most impactful thing you can do to reduce your energy and water usage when hand washing. Or ideally two bowls, if you can stretch to it.

In a recent study, researchers found that following a ‘recommended practice’ reduced greenhouse gas emissions associated with hand washing by a staggering 249 per cent.

Here’s what they recommended:

  • Fill the first bowl with hot water and the second with cool water.
  • Soak and then scrub your dishes in the first bowl.
  • Rinse the dishes in the second bowl.
  • Leave to air dry.

Now you’ve got the method down, here are some handy hints for getting sparkling results every time:

  • Start with the cleanest items such as glasses, followed by cutlery, then move onto dirtier or oily plates and bowls. Burnt-on grease on pots and pans is easy to deal with by soaking them in a few drops of good quality washing-up liquid and hot water.
  • Put aside dishes used for dairy products or anything starchy. These foods may turn gummy in hot water, so you’ll need to wash them with cold water.
  • Wash any delicate items separately to prevent chips or breaks during the cleaning process.

The eco-friendly guide to choosing a dishwasher

At this point, we may have you convinced that dishwashers are the way forward. But their energy-saving and water-saving advantages are only true for up-to-date, efficient models.

In fact, according to the consumer choice website Which? there’s a difference of £290 in energy costs over eight years between the most and least efficient full-sized dishwashers.

If you need to buy a dishwasher or want to switch to a newer model, here are our eco-friendly tips.

Study the energy label carefully

Even though it’s called an ‘energy’ label, current EU energy labels actually contain more information than just the amount of energy the dishwasher uses. For example, they also tell you the dishwasher water usage in litres per year (just look for the tap icon in the bottom left corner).

The energy label ratings range from A+++ (most efficient) to D (least efficient). And if you’re in the market for a new dishwasher, it’s worth seeing if you can find an A+ , A++ or A+++ model that suits you as these will use considerably less energy.

To get your head around the energy label symbols, check out the dishwasher section in this definitive guide to energy labels.

Go large

Dishwashers come in a range of sizes, but generally full-sized dishwashers (12-plus place settings) are the most energy and water efficient.

That said, it does depend on the size of your household. After all, if you’re living alone you might run out of plates before you fill up a 12-place setting dishwasher.

Choose a dishwasher with an eco program

Eco or energy-saving programs shouldn’t affect how clean your dishes are (as long as you follow our tips above) and they’ll definitely save energy and water.

These programs are pretty commonplace among dishwashers on the market today. But don’t assume the model you’ve chosen will have one. Always check before you buy.

Looking for more ways to save water?

Washing the dishes is just the tip of the iceberg when it comes to using water around your home. If this guide’s got you all fired up and ready to save those litres, you’ll want to read all about other clever ways to save water while cleaning.

Originally published