Today, I treated myself to lunch out, rather than cooking for myself. The restaurant where I bought my food, like nearly every restaurant, gave me the option of eating there, or “to go.” And, after I got my food (for there), I had to pick up some silverware before selecting my seat. I had the option between the “for there” silverware: standard metal forks, knives, and spoons, or the “to go” option: plastic. So, that got me thinking. I’ve been trying to focus on the virtual water content of what I eat and what I wear, but I’ve forgotten about the every-day items, like dishes. And it’s hard to say which will be more water-conscious. After all, it probably takes more virtual water to make the metal silverware than to make plastic, but the metal will last significantly longer, amounting in more savings overall. But how much is that savings offset by the water used to wash and reuse metal silverware?
So, let’s do some math. First, let’s state the obvious: reusable silverware lasts just about forever. Think about it. When is the last time you had to go to the store and buy a fork? Plastic cutlery, on the other hand, is only one-time use, so the water footprint will add up much more quickly if you use plastic silverware – it takes ten times more energy to make reusable products, but if you use an item eleven times, it’s already the greener option. Plus, the discarded plastic that can end up in landfills poses the potential to pollute water sources as it disintegrates, leading to further destruction of water.
How much water do you use washing silverware? If you wash your dishes in a dishwasher that’s relatively up-to-date, you’ll use about 10 gallons a load. If you put 20 utensils in your dishwasher (and if you’re like me, you load it way fuller than that, but let’s say 20 for the ease of math) you can anticipate using about half a gallon of water per dish washed.
If you wash dishes by hand, and don’t run the water while scrubbing, you’ll use about twice as much water, so a gallon of water per dish. Meanwhile, to make one kilogram of plastic, you’ll use about 49 gallons. A plastic fork, spoon, or knife weighs about .005 kilograms, meaning that to make a single plastic piece of plastic cutlery, you’ll use about a quarter of a gallon of water.
Does that mean plastic silverware is greener than reusable metal silverware? Perhaps, if you only wash twenty pieces of cutlery in each load, or if you hand-wash your dishes. However, if you have a dishwasher, and if in addition to washing your utensils, you also wash your plates, cups, etc., reusing your dishes ends up being far more water-efficient.
So what’s the takeaway? Load your dishwasher fuller to get the most out of your water. Never run it with fewer than 19 items in it. And if you hand-wash your dishes, or you wash fewer dishes at once, you might want to consider switching to plastic - although biodegradable cutlery that won’t pollute water sources is definitely preferable, due to plastic’s tendency to release chemicals into the ground as it decomposes.