Washing dishes can use a lot of water on a boat. Over the last 15 years, I’ve perfected my technique so that I only use about a quart/liter of water a day. These are the steps I use.
Scrape Food Off
First, I thoroughly scrape the dishes. I use a great silicone spatula/scraper (Amazon) and all the food waste goes into whatever jars or other containers I can find in the trash. Scraping well does three things: less to wash off, reduces the chances of a drain clog, and puts less food waste into the ocean (which is bad for a host of environmental reasons).
Stack Dishes in the Sink
Next I stack the dishes in the sink without rinsing. Silverware goes into a cup, with the dirty end down. I stack the plates, bowls, and pans.
I reuse other water to soak dishes. During the day, as I may rinse my hands, I do it with one of the dishes right underneath to catch and re-use the water to soak and rinse the dirty dish. Leftover coffee or water I drain from from a can of vegetables gets used in the same way, or to fill up that coffee mug with the silverware. Pasta water drains over the dirty dishes. In short, it’s very, very rare that I use otherwise “unused” water to rinse a dish or soak a pan.
When I do dishes, I take a cup or glass and fill it partially with “unused” water and a bit of dish soap. I wet my dishrag in it and then wash a dish. I start with the cleanest things and work my way to the dirtiest. My absolute favorite dishrag is my Lunatec Scrubr, which has enough “grit” to it to make cleaning easy, and the material just never, ever gets stinky. (You can get yours from Amazon.) If I need more scrub power, I use a stainless steel scrubby (Amazon).
To rinse, I use my Aquabot, also made by Lunatec. An Aquabot is really the secret to washing dishes with only a tiny bit of water. It turns a standard 1-quart/liter wide-mouth water bottle into a mini tank sprayer, so that I have pressurized water to rinse dishes, but uses far less than my sink faucet. Typically, I only use half a quart of water in the Aquabot (Amazon) over the course of a whole day. Again, I rinse right over dirty dishes so they get a little extra soak/rinse.
And that’s it. Between the dishwater in the cup and what I use in the Aquabot, it’s just 3 to 4 cups of water a day that hasn’t been used for something else already.