Lesson 6

​

How Do People Use Water?

The World Health Organization recommends that hand washing should take about 40-60 seconds.

​

How much water do you think is used during this process?

Water Usage Demo

• Capture and measure the water used for one person to wash their hands according to the World Health Organization procedure.
• Multiply the amount by the number of students in the class
• Multiply the number by the days in a week
• Multiply the number by the weeks in a school year
• How much water would your class use if you all washed your hands every day?
• Is this more or less than what you expected?

How else do people use water?

How do People Use Water?

https://www.watercalculator.org/

Classroom Discussion

​

• How much water does your family generally use?
• What are some ways you can reduce this amount?

Water is Key to Life!

• A general guideline for daily water intake is around 3.7 liters (125 ounces) for men and 2.7 liters (91 ounces) for women. However, individual water needs can vary based on factors like age, gender, climate, physical activity, and health conditions.
• The average person can only survive about 3 days without drinking water, while most people can survive around 10 days without food!

How Does Water Get Used in California?

What happens with water use as our population grows in California?

• Both agricultural and urban water use have fallen over the past two decades.
• We are becoming more efficient, even as our population grows.

The Bay Area is Also Becoming More Efficient

In the Bay Area, Homes Use the Most Water

How is water used in the home?

• Nationwide, landscape irrigation is estimated to account for nearly one-third of all residential water use, totaling nearly 9 billion gallons per day.
• Outdoor water use varies greatly depending upon geographic location. In dry climates such as the Southwest, a household's outdoor water use can be as high as 60 percent.
• In addition, some experts estimate that as much as 50 percent of water used for irrigation is wasted due to evaporation, wind, or runoff caused by inefficient irrigation methods and systems.

​

Water is Scarce

• Water covers about 70% of the Earth's surface, but most of it is salt water!
• Approximately 2.5% of all water on Earth is freshwater.
• Most of this freshwater is locked in glaciers, polar ice caps, and underground aquifers, making it inaccessible for immediate consumption.
• Significant water infrastructure is usually needed to bring water to the places where humans need to use it.

Why are freshwater resources so limited globally?

How might climate change affect our access to water ?

• Changes in Precipitation Patterns: This leads to more frequent and intense rainfall in some areas, while others experience prolonged droughts. These changes can disrupt the natural replenishment of freshwater sources like rivers, lakes, and groundwater, affecting water availability.
• Water Scarcity: Rising temperatures accelerate evaporation rates, which can cause water sources to dry up more quickly. This could lead to water scarcity and conflicts over limited water resources.
• Water Quality Impacts: Higher temperatures and altered precipitation patterns can lead to increased water temperature, changes in water chemistry, and harmful algal blooms. These factors can degrade water quality, making it unsafe for consumption and requiring additional treatment processes to ensure its safety.
• Sea-Level Rise : As global temperatures rise, polar ice caps and glaciers melt, causing sea levels to rise. Rising sea levels can lead to widespread damage to vital infrastructure.

- Shaded areas represent the shoreline communities that are most vulnerable to the effects of sea level rise and flooding within the SF Bay Area. Can you spot your community?

What does California’s variable rainfall pattern mean for residents?

• The amount of precipitation that falls in California has always been very variable. There is no such thing as an “average year.”
• Climate change predictions are that precipitation will become even more variable, with higher highs and lower lows. Our water infrastructure was built to supply water based on the historical precipitation patterns.
• Climate change means our water supply systems won’t be able to work as well as they used to.

How might climate change affect our access to water?

​

• More frequent and more severe droughts
• Less precipitation means less water in the system
• Water shortages mean restrictions on water usage and potential disruptions to daily life.
• Increased risk of wildfires and poor air quality.
• Wildfires within a watershed can result in reduced water quality from that area.
• Critical water system infrastructure can be damaged by the fires.

Image displays how drought conditions can change so rapidly in California.

How might climate change affect our access to water?

• Warmer temperatures will melt snowpack faster
• Snowpack serves as the biggest storage reservoir for our water system.
• Warmer temperatures mean less water available to the system, particularly late in the summer.
• When snow melts too quickly, the water has nowhere to go and can result in dangerous flooding.

​

Rapid snowmelt from unpredictably warm weather can cause large scale flooding and widespread damage to infrastructure

How can one become more water efficient inside your home?

1. Try to only fill bathtubs halfway or less: Filling up your bathtub halfway or less can save up to 17 – 25 gallons of water per person every bath.
2. Installing High-Efficiency Toilets: Try to convince your parents or the adults at home to install high efficiency toilets, these toilets can save 6 – 35 gallons per day.
3. Take shorter showers: Keeping your showers under 5 minutes can help save 12.5 gallons per shower, when using water efficient showerheads.
4. Turning off water when brushing your teeth: By turning off the water when brushing your teeth, you can save up to 8 gallons of water per person per day.
5. Fixing leaks around the home ( Faucets, Toilets, Water heaters, etc.) . Fixing leaks at home can save between 27 to 90 gallons of water every day.
6. Water efficiency & appliances: Doing fewer loads of laundry and utilizing appliances that have an EPA WaterSense label can go a long way toward saving water and money on your utility bill.

​

How can one become more water efficient

outside your home?

1. Use a broom to clean outside areas: Using a broom to clean outside areas instead of a garden hose can save 6 gallons of water every minute.
2. Water the plants that matter most! : Feed your vegetable and fruit plants water because they feed you. Water wise plants and shade trees use little, or no water once established. Lawns should be the lowest priority.
3. Use water wise plants: Check with your local water agency on the best plants for your area. It is best to use water-wise and native plants when planting or transforming your yard.
4. Removing ornamental turfs and grasses: Turf grass requires significant amounts of water to maintain its green and healthy appearance. Removing turf can help conserve water resources, especially in areas facing water scarcity or drought conditions.
5. Maintain healthy soils: Healthy soils are the basis for a water-smart landscape; they effectively cycle nutrients, minimize runoff, and retain water.
6. Utilize mulch within a landscape: Incorporating mulch around shrubs and garden plants can help reduce evaporation, inhibit weed growth, and moderate soil temperature.�

Image of a home that has decided to scrap their traditional grass lawn for a water efficient front yard.

Water Can Be Recycled Too!

• Recycled water is wastewater that has been treated and repurposed for use. Traditional recycled water has only been used for non-potable uses like irrigation and toilet flushing. Now, some areas are starting to treat recycled water to levels where it can be used for drinking!
• Every drop of recycled water we use helps reduce the strain on our freshwater supplies.