The answer to the first question is: It depends on a number of different factors. If you are careful and methodical while washing dishes by hand, it is possible to reduce your water usage dramatically. Water usage can vary dramatically from one dishwasher model to another. So there really is no clear-cut answer.
If you want to wash dishes by hand using the least amount of water, start with the smallest items, use your rinse water to fill the washbasin, and turn off the tap when you are not rinsing something. This way, you’ll recycle your rinse water from silverware so you can use it to wash larger items like pots and pans.
If that method sounds too time-consuming, the good news is that there are simple ways that you can load and run your dishwasher to maximize its efficiency and effectiveness.
If you have a newer dishwasher model, you probably don’t need to pre-wash dishes before loading the machine, unless they have stubborn caked-on food. Often, you can just scrape or wipe food off dishes instead of pre-washing them. That will save you both water and time.
When it comes to loading your dishwasher, start on the bottom, and keep tall items like cookie sheets or large plates on the outer edges so they won’t block the water jets. Arrange smaller and dirtier items toward the center of the lower rack.
Glasses, plastic storage containers and other small items should go on the top rack, but be careful not to pack them too tightly to ensure that water can get between them.
Be sure to use the correct detergent for your machine. Consult your owner’s manual for your manufacturer’s recommendation. It’s also smart to experiment with different types of detergent to find the one that works best with the water in your area. Hard water can inhibit the performance of some detergents.
Finally, to maximize energy efficiency, only run your dishwasher when it is totally full. It takes the same amount of energy to run a cycle when the machine is packed as it does when it is half-empty. It’s a common myth that your dishes will be cleaner if you run smaller loads. As long as you follow the correct loading procedures, you’ll get more bang for your buck from a full load.
If you absolutely need to run a smaller load, be sure to select the “light wash” or “energy saver” option on your machine. And turn off the heated dry option for further energy savings.
Whether you choose to wash dishes by hand or to use a dishwasher, one thing remains the same: With the proper preparation and diligence, you can minimize your use of both water and energy. And that can save you money in the long run.