Wash the dishes twice to save water!
Home water conservation has always been a bit more difficult for those of us who live in rental apartments. The incentive just isn’t there to Invest in low flow faucets, fixtures, and appliances, for a property you don’t own. I started tracking water use about 5 years ago and was amazed to find that my wife and I consumed, on average, 55 gallons (208 L) per day. This is actually below the average of 120L/person/day in Germany, but I still couldn’t quite figure out where all that water was going. Over this period I tracked our water use, we moved 3 times, however the average water use was fairly consistent. We did have 7-kg front-loader clothes washing machines in all 3 apartments and none had dishwashers. I decided there were 3 areas that I needed to look at; faucet flow rate, toilet flush volume, and dishwashing technique.
I go into more depth about faucets and toilets in “Life with My Grey Water Bucket”, but let’s look a washing the dishes first. My method for washing by hand was a bit sloppy. Many times I caught myself just allowing the water to run throughout the process, occasionally draining the sink to stop it from overflowing. I knew it would be difficult to ever wash dishes as water efficiently by hand, as by machine, since high efficiency dishwashers consume as little as 3 gallons (11.4 L) per cycle, but investing in a dish washer was not really an option for us, so finding a better system for washing dishes by hand, was the only solution. After researching tips on how to wash dishes I develop a technique, largely through trial and error, that seems to work. I discovered the most efficient method is to essentially wash everything twice….that may seem counter intuitive, but it actually works well. The first wash is really more of an aggressive rinse. I fill the sink with 1” to 2” (2.5 -5cm) of water…basically deep enough to submerge a dinner plate, then wash (no dish soap at this stage) all the plates, cups, dishes, utensils, pot, etc. in this water, without adding additional water. I’m not trying to get the dishes completely clean at this stage, I just try and remove as much food residue as possible. I found using a nylon dish brush for this step is useful for getting rid of 99% of the grime. At the end of this process I have a stack of, not quite clean dishes on the counter, and some really mucky water in sink. Next, I drain the water from the sink and rinse the sink to get rid of any residual food scraps or grease. For the “second wash” I just repeat the process using a couple inches of clean water and dish soap…use an eco-friendly brand. One excellent tip I found in my research was not use too much dish soap; just enough to clean, otherwise you’ll use a lot of water trying to rinse off all that soap. Once everything has gone through the second wash, I then turn on the faucet, at a low, but steady rate, and rinse. I do not drain the sink before the rinse process, as I’ve that allowing the sink to fill as I rinse gives me immediate feedback to how much water I’m using. The water remaining in the sink at the end of the rinse can be siphoned into a bucket and reused for other purposes…see “Life with My Grey Water Bucket”. I estimate that washing the typical batch of dinner dishes, for 2, uses about 6 gallons (23 L) of water total….still not as efficient as a machine for the same volume of dishes, but not bad for a mere human.
Living with my grey water bucket
As I talked about in early post, over the years I had become increasingly concerned about what I felt was an unreasonably high amount of water usage on the part of my wife and me. Our daily water usage tracked at about 55 Gallons (208 Liters) per day, regardless where we lived over a 5 year period. I decided on a 3 prong approach to try and get the numbers down: 1- improve faucet flow rate, 2- reduce toilet flush volume, 3- more water efficient dishwashing (See : “Wash the dishes twice to save water!”)
When I measured the flow rates from the various faucets, including the shower, I discovered that some savings could be made by purchasing low flow aerators. Since these are items that are easy to uninstall and take with you when you move, it is a reasonable investment for any renter to make. Most of the faucet in our current apartment had a reasonable flow rates, the exception being the bathroom faucet which was putting out about 3 gal/min (11.3L/m) at full flow, with a low flow aerator I got this down to 1.2 gpm (4.5L/m). The shower was already pretty good, about 2 gal/min, even though I could have invested anywhere from $50-$400 and decreased the flow to the 1.8 – 1.3gpm (6.8-4.9L/M) range, (See: “LEED Points vs Water Conservation”) I decided that simply being a bit more efficient, timewise, in the shower, was good enough.
My next point of focus was the toilets. By recording the water meter reading before and after a flush, I was able to determine that the toilet was very inefficient, nearly 3 gals/flush (11.4 Ltr). Fortunately in Germany where we live some toilet mechanism work in such a way that you can stop the flush at any point, so after some experimenting I found about 3 seconds was equivalent to 1.6 gals. (6 L.). There are other strategies you can employ with toilets, such as not flushing after every use…the so called “if it’s yellow let it mellow” strategy. , or using grey water to flush the toilet…thus the great grey water bucket experiment.
I noticed that there were a few water uses in our apartment that could be, with minimum effort, reclaimed and reused. The simplest was our condensing clothes dryer. The water from the drying cycle is retained in a reservoir and can easily dumped into the designated grey water bucket. The second was water lost in the shower. Typically we all turn on the shower and give the water a chance to warm up stepping in. By simply placing the grey water bucket in the shower to capture the water during this period is an easy way to catch water that is otherwise lost down the drain. The third and probably most difficult source to reclaim, was dish washing water. This requires siphoning the water out of the sink and into the bucket. I had in mind 2 primary uses for my grey water: toilet flushing and watering plants. I have to admit that using it for toilet flushing requires a level of dedication that the average person probably does not possess. Although simple; you just dump the water into the toilet bowl (aim, as always, is important) the logistics of always having to schlepp the water into the bathroom and hygiene issue of the inevitable splashing, really makes it something more for the diehard water conserver. Using the water for watering plants turned out to be a more practical use for the water. I our particular case we have about 20 linear feet of window boxes and several other potted plans, so in during the hot summer months, consumptions can be as much as 20 gallons /week (80 liters).
After implementing all my strategies, I was able to cut our water consumption by more than half to 24 gals/day (91 Ltrs). As I wrote above, I did find the “grey water bucket” was a difficult practice to sustain with regards to toilets, so in the following months consumption went up and settled around 35 gal/day (132 Ltrs), but this is a vast improvement, 36% less, then where we started.