Water Conservation within the Home by Elizabeth Molek (W&R 1)

Elizabeth Molek

Math 33

Professor Deforest

9 October 2017

I’m going to discuss the issue of water conservation that is constantly a persistent problem most people struggle with, especially college students. I don’t know about others, but I wish to see the world in 200 years with clean water still available. Water is our most precious resource, and despite being the most abundant only one percent of it is drinkable so it is imperative that we keep this one percent clean and that starts with conservation. The best way for the average person to help conserve water, starts within the home. Hand washing dishes and using the dishwasher (a huge water usage source in the home) to see which is more eco friendly will be discussed further below in this paper. Despite most of the water usage in our nation being put out on agriculture and the cooling of power plants, all of us can still make a difference by finding out through small observations how they can best save water (Freshwater Crisis). For example, investing in high efficiency washing machines and dishwashers may be worth it and cut down future utility bills, and/or cutting down shower time could solve the trick too. The overall goal is just to take a minute out of the day to realize when and how much water you actually use, and the impact that brings on to the environment. Below is a demographic on where most water is used on which resources in the United States. As one can see as stated above, most water is used for irrigation and thermoelectric power.

(Frac Focus. Com)

Most people today rely on water to do a lot and there’s no doubt that water is a part of everyday life for all people whether they are using it to shower, drink, clean, and to irrigate crops, etc. In this piece I mathematically intend to figure out whether it is more efficient for my apartment in State College, PA to use the dishwasher once a day or to hand wash them in small quantities in individual time settings. First I kept a log of water usage next to our sink, and had my roommates fill it out. I then did calculations with this information and compared it to research I did about dishwasher water usage to come to a final conclusion.

After working out all of the math and tests that are to come below, it is in fact more environmentally friendly and cost efficient to run the dishwasher once a day than to hand wash dishes. By preforming this small test, my roommates and I were able to be able to determine which method saves water, which will now help save the environment and our utilities bill.

To first determine this theory, we must first look at how much water comes out of an average faucet. My apartment’s plumbing is old; to make an educated guess I would say the pipes could be about fifteen to twenty years old. Taking note of the gallons per minute that flow out of each individual faucet is very effective. On average a gallon flows out of bathroom/kitchen faucet at the rate of two gallons per minute (Dunn). However, we tested this in our kitchen to determine the actual flow rate for the most accurate results. By putting an old gallon jug under the faucet we found out that one gallon of water flows out of our faucet every forty seconds. So one and a third of a gallon flows out of our kitchen sink per minute. Knowing and understanding this rate made it much easier to know exactly how much water we used when we logged our wash times over the course of three days.

The next step to determining our mathematical question was to simply figure out how much water we used over the course of a day when we were handwashing our dishes. We kept a log right next to the sink and I simply asked all my roommates to log the amount of time the water was running in the sink when they were using it. On morning one the total was 6 minutes 37 seconds of the sink water being ran. By the end of the day we logged a total of 14 minutes and 56 seconds of using the sink with the water running. By doing the math, the amount of water we used in one day was staggering.

R= \( 1 \frac {1}{3}\text {gallons}\) per minute

\( 15 minutes \times\ 1\frac {1}{3}\text {gallons}\) = 20 gallons of sink water per day on dishes

We continued to conduct the log for 3 days in a row, on day two we used 25 gallons of water and on day three we used 19 gallons of water on dishes.

I kept this information close and realized on average my apartment with four people making around three meals a day was using around 21 gallons of water, just to wash the dishes that were dirtied from these meals. Our dishwasher is a Kenmore and is probably around ten or more years old. Our dishwasher uses on average, as the manual claims, ten gallons per load. Below is a graphic from US EPA Energy Star, showing how newer dish washers use as little as four gallons per load. After comparing the two factors I realized in our situation it is more effective to use our dishwasher, and run it once at the end of the day. Weekly we are saving a lot of gallons as done out below.

Dishwasher:  \(10 {gal} \times 7 \  {days}\) = 70 gallons a week

Hand washing: \(20 {gal} \times 7 \ {days}\) = 150 gallons on average per week

*if using correct significant digits for the final answer it would be too far off being 200, so one extra digit was used*

Our apartment saves on average around 77 gallons per week on water by loading our dishwasher. Basically we save one standard bathtub full of water each week, which is about 80 gallons (Erlam).  Even though it is not an energy star, and it is not the most recent it still proves effective. The image below shows the average water usage of dishwashers per era. This made me realize that even the dishwashers in 1980 were still more effective than our handwashing is currently.

There are many ways the average consumer can be still enviormentally friendly even if they do not have a dishwasher available. To have effective dish hand washing skills one can fill the sink with water and keep it plugged all day creating a small pool. Washing each dish as dirtied in this water, then rinsing it after, using a minimal amount of water. If one hand washes dishes this way it keeps water usage to a minimum, and allows someone without a dishwasher to conserve their water usage. Using a dishwasher, or hand washing effectively can both be beneficial to the environment, it all depends on which was is best for you.

Thanks for following through my mathematic environmental analysis I conducted. Small tests like these can be done by anyone who wants to make a difference. By figuring out how much water my sink put out per minute, calculating how much water our dishwasher used per load, and adding in outside factors such as the time log and loads per day, I was able to successfully determine the using the dishwasher once a day is beneficial to the environment tremendously, at least for the average college apartment. Hopefully next time you debate whether to hand wash or preload your dishes in the automatic washer this piece will be in the back of your mind.


Works Cited

Dunn, Collin. (2009, 22 January). Built In Dishwashers vs. Hand Washing: Which is Greener? https://www.treehugger.com/kitchen-design/built-in-dishwashers-vs-hand-washing-which-is-greener.html

 Erlam, Linda. (2016, March). How much water will an average Bathtub Hold? http://homeguides.sfgate.com/much-water-average-bathtub-hold-81697.html

Freshwater Crisis. (2010). http://www.nationalgeographic.com/freshwater/freshwater-crisis.html

GE Energy Star Certified Dishwashers. (2017). http://www.geappliances.com/ge/energy-star-appliances/dishwasher.htm (Credit for second Image)

Hydraulic Fracturing Water Usage. (2017). https://fracfocus.org/water-protection/hydraulic-fracturing-usage  (Credit for first Image)

Perlam, Howard. (2016, 2 December). Water Questions & Answers. How much water does the average person use at home per day? https://water.usgs.gov/edu/qa-home-  hhhhhhhhhhpercapita.html

 (Links to an external site.)


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6 Responses to Water Conservation within the Home by Elizabeth Molek (W&R 1)

  1. Rachel Stone says:

    This Write and Respond post was very eye opening. I predicted at the beginning of your article that hand washing would have been the better way to go. I’m glad I learned that is not the case. I think putting a log by the sink in your apartment was a great way to collect your data as well as having all your roommates fill it in as well. I know my water usage is different than others so that was a great way to get a more averaged estimate. Also, great idea to test how much water comes from your faucet per minute with the gallon jug, I didn’t think it would have been a gallon every 40 seconds. In addition, relating the amount of water your apartment saves every week by using the dishwasher to the amount of water in a standard bathtub was a great comparison because it was something I could actually picture in my mind. Thanks for sharing your indings! I think everyone should look at small ways to reduce their water consumption like you said by taking shorter showers or using a dishwasher!

  2. Riley Nicole Schear says:

    Hi! Your writing was very interesting. Conserving water is a very important topic and many people take water for granted. You made great points on how people over use water daily. At home I try and take shorter showers and not leave the sink on as long. You also collected your data in a very smart way. There are many different ways we can save water that people might not realize. I learned new ways of saving water by reading your article! I believe many people need to re think how much water they use.

  3. zml5135 says:


    I found your article extremely unique and interesting. I loved how instead of just Googling average numbers of water for hand washing dishes you actually went out and produced your own data. I also performed my W&R on water usage in the home, but on a different appliance, the washing machine. What surprised me the most about your post was how close to the amount of water used for washing dishes was to washing clothes. Personally, I would have thought that washing clothes would use way more water than washing a few plates and utensils. This goes to show that water usage is greatly overused more in some areas of the household, washing dishes, than others, washing clothes. I was strongly advocating for users to switch their washing machines to better models for water usage, but after reading your W&R post it has made me realize how easier (and cheaper) it is to save water in some areas of the home than others. Coming across the same issue in my apartment, I am now going to put a higher emphasis on using the dishwasher for the rest of the year.

  4. Ashanti Rubin says:

    Hey! I really enjoyed reading your article because it really related to mine. I calculated my personal water footprint and how much water that I personally use, and that was eye opening to see how much is wasted. When I read that you hope that in the next 200 years that you hope that there is still clean water left, I totally get what you mean. People dont realize the amount of water we use and how important of resource it is. All water circulates so when it runs out, theres no more. It was great that you offered some suggestions on how to save water. I thought that made your post great, because what better way to introduce a problem without giving some solutions.

  5. zhaoyang wang says:

    In this article, you talk about which is the most efficient way to save water, the dishwasher or hand wash. I was surprise that using dishwasher is actually more efficient than using hand to wash the dish. I have dishwasher in my home, but I am not actually using it, because it takes a long time, like half hours to wash all the dishes, and sometimes I think the serval dish is not necessary to use the dishwasher. So, I think using dishwasher will spend a lot of water and it is feels so wasteful. But this article challenged my idea, the dishwasher is more efficient than hand wash, dishwasher is going to spend 70 gallons and hand wash will spend 150 gallons. In this way, it can save 77 gallons. that is a lot of water. And I didn’t notice that using hand to wash the dishes is so wasteful, because when you wash the dish by your hand, the water is actually run away. Which will spend more water than using the dishwasher. And it is so funny that he gives the picture about the gallon by showing the water bucket. I have no idea about what does 77 gallon looks like. But according to the picture he shows, 16 gallons is a big water bucket. So, the 77 gallon is amount of water that I can imagine. Besides, the work cited he provide is also interesting, it closely related to the topic he discussed. So to sum up, it is an article that challenged my old idea.

  6. Erin Brennan says:

    I really enjoyed reading your blog post! It’s very informative and easy to follow since you broke down the steps when explaining how you conducted your experiment. I was surprised to learn that dishwashers save more water than hand washing does. I don’t have a dishwasher in my apartment, so learning how much water I’m wasting when doing the dishes for 5-10 minutes made me realize I should be more aware of how long I keep the faucet running while cleaning. I agree that water conservation is an important topic that a lot of people neglect since water is a source we access so easily and frequently. I feel like everyone should be more conscious of how much water they use for basic things like washing dishes or brushing your teeth. Hopefully, people will feel more obligated to do so after reading this post.

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