Whenever I wash the dishes at home, I constantly ask myself:
“Is the dishwasher more water-efficient than washing the dishes by hand and… do I really need one?”
If you’ve thought about water conservation like me, then you’ve probably asked yourself just how much water do all those appliances consume every day? In today’s article, we will try to dive as deep as we can to learn more about hidden water consumption in your home, as well as discuss some of the emerging technologies that can help us reduce our water footprint in our daily lives.
Let’s begin by first looking at the data we have on water consumption per capita in the United States from 1980 to 2015 [1]. (Note that the data includes water consumed by people, industrial, irrigation, and other usages.) From the data, we can observe an increase in population and a decrease in water consumption per capita. By multiplying those numbers, we can actually derive that the overall water consumption in the United States is dropping year over year; however, this does not help alleviate the upcoming water crisis which we discussed in the previous article “Water: Soaring Demand But Less Supply ” [2].
Based on the graph above, we know that the water consumption per capita in the United States in 2015 was around 1,200 cubic meters per year (≈ 317,000 gallons per year = 868 gallons per day). So, how does this number compare to the global average water consumption? According to statistics shown in “Our World in Data” and the global population, the global average water consumption is around 550 gallons per year [3].
The images above show the overwhelming gap between the global average consumption and US consumption which means that an average US household utilized 318 gallons more than the average and it is 17% to 60% of the other well-developed countries, such as France or Japan [3].
Now we have looked at how water consumption is broken down at the global level, let’s observe how it impacts the typical household and understand what the main water-consuming contributors are. Before we dive into those datasets, let’s spend some time thinking about what factors account for the most water consumption in your house, and I will present you the data later.
Here are the top “water consumers” in your home that I think are important to know:
- Machines: Laundry machine/Dishwasher/Sprinklers
- Personal Use: Drinking water/Showering/Handwash/Brush Teeth
- Miscellaneous: Car wash/Cooking/Toilet/Leak
- Other Hidden Factors
To further explain what hidden factors are, they may be considered “Virtual Water” by the scientific community as they define it as the amount of water you use that is not visible to you. To give you a better perspective, virtual water can be found in the products we purchase such as vegetables and meats which we consume. The concept of virtual water was first introduced by Prof. Tony Allan in 1993 [4]. He proposed the concept to let us better understand water issues and how they are linked to agriculture, climate change, economics, and politics.
The Breakdown of Virtual Water
To better understand what virtual water is, let’s look at the food we consume on a daily basis — We will use raising cattle for beef as an example.
A rancher needs to prepare 1,300 kg of grains just to feed a cow in a 3-year span. These grains require water to grow, the cow needs to drink, and the slaughterhouse needs to be cleaned. In general, roughly 18 cubic meters of water (≈ 4,068 gallons of water) will be needed if we want to enjoy one kilogram (≈ 35 oz) of a juicy steak [5].
Now we have a better idea of how water is hidden and used in our daily lives. Below is a breakdown of how 868 gallons per day in a US household are broken down for reference [6].
Laundry: 23 gallons per day per person
Faucet: 26 gallons per day per person
Toilet: 33 gallons per day per person
Leaks: 17 gallons per day per person
Showering: 28 gallons per day per person
Dishwasher: 2 gallons per day per person
Vegetation (e.g. lettuce): 2 gallons per leaf
Meats (e.g. turkey): 520 gallons per kilogram
*The data is collected from Residential End Uses of Water, Version 2 [7].
The dataset presented reveals that using a dishwasher may be the most water-efficient method to clean our dishes as hand washing may use up to 20+ gallons of water per cycle [8].
Now, let’s compare the use of both virtual water and visible water consumption, on average each person may consume more water than we originally thought, highly depending on their diet roughly between 320 ~ 868 gallons.
Given these facts, you may start thinking if there are any ways or technologies that we could use to help reduce our water footprint. The short answer is “yes”. There are some technologies that can help you collect grey water, and this is where I personally believe may become mainstream technologies in the near future. Here are a couple of examples of technologies currently out there for your reference:
Hydraloop — Help Save Up To 45% of Water
“In-house water recycling is the most efficient and affordable way to use less tap water. Hydraloop collects, treats and re-uses the water from showers, baths, washers and dryers, heat pumps and air conditioning units. Depending on the configuration and user behavior up to 45% of total in house water consumption can be saved. Hydraloop water is clean, clear, safe, and disinfected. It can be re-used for toilet flushing, laundry, garden irrigation and topping up swimming pools.”
Ecovie Water Management
“Green rating systems such as the International and Universal Plumbing Codes and LEED for Homes, Building Design, and Construction recognize water management and the NSF350 C greywater recycling standard under which Ecovie’s Aqualoop system is certified.
We approach each project as a unique and valuable partnership, and we strive to deliver the best possible solution for you, while communicating openly every step of the way. Our main focus is on grey water recycling and rainwater collection. We also tackle black water recycling and stormwater management.”
These technologies are currently on the market and can help recycle secondary water (a.k.a grey water) and further reduce water consumption. Although they treat relatively small amounts of water, they can significantly help the community as a whole to be more sustainable in the way we consume water.
Another thing that we could do to reduce consumption is to rethink our diets. The benefits are not only that we can make a positive impact on the environment, but also we may be healthier in the long run when we consume items that have a lower virtual water consumption which can mean a less meat-intensive diet. (Just saying)
Thank you for reading this article! Your contribution and support always motivate us to continue being innovative!
[1] Water Withdrawl. 2022. OECD.
[2] Water: Soaring Demand But Less Supply. 2022
[3] Water Use and Stress. 2015. Our World in Data.
[4] Honouring Professor Tony Allan, the inventor of ‘virtual water’. SIWI.
[5] Average Daily Water Usage. The WORLD COUNTS.
[6] Water in Daily Life. US EPA.
