Water is everywhere, which is fortunate for all of humanity, as water is essential for life. Even though water is not always available in the needed quantity and quality for all people everywhere, people have learned to get and use water for all of their water needs, from drinking, cleaning, irrigating crops, producing electricity, and for just having fun.
• Water Science School HOME • Water Science Q&As •
Water Use Questions & Answers
Here are some questions and answers about water use that may interest you:
Where does our household water come from?
The U.S. Geological Survey (USGS) compiles national water-use information every 5 years, with the last compilation done in 2015. As far as where all the water is from that we use in our homes, it is from either a groundwater source, such as a well, or from a surface-water source, such a river, lake, or reservoir.In the U.S. in 2015, about 283 million of the 325 million people in the United States got their home water delivered by a public supplier, such as the county water department. At other homes, mainly in more rural areas, people provide water for themselves from sources such as a well, a cistern, a pond, or a stream. It is common that groundwater wells provide water for these users, with almost 98% of water coming from fresh groundwater sources.
How much water do I use at home each day?
Estimates vary, but, on average, each person uses about 80-100 gallons of water per day, for indoor home uses. Are you surprised that the largest use of household water is to flush the toilet, and after that, to take showers and baths? That is why, in these days of water conservation, we are starting to see toilets and showers that use less water than before.
Many local governments now have laws that specify that water faucets, toilets, and showers only allow a certain amount of water flow per minute. Water agencies in some areas, such as here in Atlanta, Georgia, offer rebates if you install a water-efficient toilet. Yes, these toilets really do use a lot less water. For your kitchen and bathroom faucets, if you look real close at the head of a faucet, you might see something like "1.0 gpm", which means that the faucet head will allow water to flow at a maximum of 1.0 gallons per minute.
How is sewage and wastewater treated?
Different treatment is used depending on the source of your water. Groundwater taken from wells has been filtered through rocks, so it is usually quite free of particles. It can still contain chemicals and organic matter that must be taken out, though.
If your water comes from a surface-water source, such as a river or lake, some work must be done to get rid of particulate matter. Often water is withdrawn and pumped into holding ponds or containers, where solids and particles can settle to the bottom. Possibly filters and sand beds are used to screen out particulate matter, and at a minimum, chlorine is added to kill dangerous bacteria and microorganisms.
Why does my water smell like rotten eggs?
You would know it if you had this problem! A frequent cause of musty, earthy odors in water is naturally occurring organic compounds derived from the decay of plant material in lakes and reservoirs. In some parts of the country, drinking water can contain the chemical hydrogen sulfide gas, which smells just like rotten eggs. This can occur when water comes into contact with organic matter or with some minerals, such as pyrite. The situation mostly occurs as groundwater filters through organic material or rocks.
Water containing hydrogen sulfide can have an odor that is objectionable (and the water may taste really bad), but generally the water is not harmful to health. However, odors can be caused by other constituents as well, so you may want to call your local Health Department and mention the odor to them. The best way to find out what is in your water is to have the water tested by a state certified laboratory. A list of these labs is available from the U.S. Environmental Protection Agency State Certification Program. Your local county Extension office may also offer water testing.
Where does our home wastewater go?
Water leaving our homes generally goes either into a septic tank in the back yard where it seeps back into the ground, or is sent to a wastewater-treatment plant through a sewer system.
Different treatment is used depending on the type of water coming into the plant and the water-quality requirements of water leaving the plant. Often the first stages of water treatment are purely physical methods, such as letting solid particles settle to the bottom of a holding tank and filtering the water through sand or other fine particulate matter. Filters are used to screen out large particles, and at a minimum, chlorine is added to kill dangerous bacteria and microorganisms.
A typical set of steps to treat water:
- Odor control: Chemicals can help keep down foul odors
- Screening: Move water through screens to separate larger solids and trash
- Primary treatment: Move water into large tanks and allow solid material to settle at the surface. Scrape material off and dispose of it
- Aeration: Stir up the water to get it to release gasses, and pump air through the water to allow bacteria to act on organic matter to help it decay.
- Remove sludge: Solid material settles to the bottom and removed
- More filtration: Filter water through sand, for example, to reduce bacteria, odors, iron, and other solids.
- "Digest" the solid material: Hold and heat the solid material to break it down to nutrient-rich biosolids and methane gas
- Disinfection: Water is treated with chlorine to kill bacteria
Wastewater treatment plants can treat sewage and create water that can be used for other purposes (relaimed wastewater).
Some systems have additional water treatment that use biologic processes to remove organics, nitrogen, and phosphorus, a membrane tank to remove bacteria and suspended solids, ultraviolet disinfection to render viruses inactive, and aeration to raise the oxygen level (needed by fish living in the river where the treated wastewater is dumped after cleansing).
How much water falls during a storm?
In other words, when I have a big storm over my house, just how much rain am I getting? Let's say your house sits on a one-half acre lot. And let's say you get a storm that drops 1 inch of rain. You've just received 13,577 gallons of water on your yard. A big bath holds about 40 gallons of water, so if you could save that inch of water that fell you could take a daily bath for 339 days! Let's expand that to a city. Atlanta, Georgia has corporate boundaries that cover about 84,100 acres (U.S. Census Bureau). A 1-inch rainstorm deposits 27,154 gallons on one acre, so during this storm Atlanta receives 2.28 billion gallons of water.
In this era of water conservation, many homeowners are putting "rain barrels" around their homes to collect rainfall runoff. Essentially, this is just a large bucket to collects water coming off of the roof and down the gutters and downspouts. The water is then used to water gardens and plants. Can you get enough water out of the gutter to make it worthwhile? The answer is definitely "yes". A typical outdoor trash can holds 32 gallons. If you capture the rainfall runoff from a storm that just produces 1/10th of an inch of rain onto a 20 by 30 foot roof, you end up with a full 32-gallon container full of water, with 5 gallons left over.
You can use our handy "How much water falls during a storm" calculator to find out how much water falls during a rainstorm for a chosen sized area.
Does a little leak in my house really waste water?
It's not the little leak that wastes water—it is the little leak that keeps on leaking that wastes water. And the fact that the leak is so little means that maybe you ignore it. So, how can a little leak turn into a big waste? Many of our toilets have a constant leak—somewhere around 22 gallons per day. This translates into about 8,000 gallons per year of wasted water, water that could be saved. Or think of a leaky water line coming into your house. If it leaks 1 gallon of water every 10 minutes that means that you are losing (and paying for) 144 gallons per day, or 52,560 gallons per year.
There is no scientific definition of the volume of a faucet drip, but after measuring a number of kitchen and bathroom sink faucets, the volume seems to be between 1/5th and 1/3rd of a milliliter (mL). Drips from bathroom tubs come in a bit more, though, at about 1/2 mL. So, we are going to use 1/4 mL as the volume of a kitchen faucet drip. So, by these drip estimates:
- One gallon: 15,140 drips
- One liter: 4,000 drips
Looking at it this way, it seems like that drop of water down the drain is pretty insignificant. But, if you use our handy Drip Calculator, you can see that all those drops flowing in "real time" can really add up to a flood of wasted water.
What makes a groundwater well go dry?
A well is said to have gone dry when water levels drop below a pump intake. This does not mean that a dry well will never have water in it again, as the water level may come back through time as aquifer recharge from precipitation seepage increases and/or pumping of the aquifer is lessened. It is true that all the water in the ground comes from infiltration of precipitation from above, but the geology of the underground rock determines the infiltration and movement characteristics of the water that is in the ground.
The water level in a well depends on a number of things:
- Depth of the well
- Type (confined or unconfined) of aquifer the well taps
- Amount and rate of pumping that occurs in the aquifer
- Permeability and porosity of the underground rock
- Amount of recharge occurring from precipitation or artificial recharge
Wells in unconfined water table aquifers are more directly influenced by the lack of rain than those in deeper confined aquifers. A deep well in a confined aquifer in an area with minimal pumping is less likely to go dry than a shallow, water-table well.
How important is groundwater?
Groundwater, which is in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 33 percent of the water that county and city water departments supply to households and businesses (public supply). It provides drinking water for more than 90 percent of the rural population who do not get their water delivered to them from a county/city water department or private water company. Even some major cities, such as San Antonio, Texas, rely solely on groundwater for all their needs. In 2015, about 48 percent of the water used for irrigation comes from groundwater. Withdrawals of groundwater are expected to rise as the population increases and available sites for surface reservoirs become more limited.
About 29 percent of the freshwater used in the United States in 2015 came from groundwater sources. The other 71 percent came from surface water. Groundwater is an especially important natural resource in those parts of the country that don't have ample surface-water sources, such as the arid West. It often takes more work and costs more to access groundwater as opposed to surface water, but where there is little water on the land surface, groundwater can supply the water needs of people.
Is salt water useful?
In today's world we are all more aware of the need to conserve freshwater. With the ever-growing demand for water by growing populations worldwide, it makes sense to try to find more uses for the abundant saline water (salt water) supplies that exist, mainly in the oceans. You may not be able to use saline water to water you garden full of delicious rutabagas, broccoli, and spinach, but saline water does have some valuable uses. As these pie charts of the Nation's water use show, about 13 percent of all water used in the United States in 2015 was saline. Almost all saline withdrawals, over 95 percent, was used by the thermoelectric-power industry to cool electricity-generating equipment. About five percent of the Nation's saline water was used for mining and industrial purposes.
Perhaps one of the most important uses of saline water, and something that will become more important in the future, is that it provides a ample supply of water that can be desalinated and turned into fresh water. The processes to desalinate water is costly, though, so as costs come down it will be used more and more.
Which states use the most water?
More than one-fourth of the total water used in the United States in 2015 was withdrawn in California, Texas, Idaho, and Florida. California accounted for 9 percent of all withdrawals in the United States in 2015. Nearly three-fourths of the freshwater withdrawn in California was for irrigation, and 98 percent of saline water withdrawn was for thermoelectric-power generation.
In 2015, more than 50 percent of the total withdrawals in the United States were accounted for by 12 States: California, Texas, Idaho, Florida, Arkansas, New York, Illinois, Colorado, North Carolina, Michigan, Montana, and Nebraska.
https://labs.waterdata.usgs.gov/visualizations/water-use/index.html
What is most of the freshwater in the U.S. used for?
The water in the Nation's rivers, streams, creeks, lakes, reservoirs, and in underground aquifers are vitally important to our everyday life. Although saline water is used for some purposes, mainly to produce electricity, when people think of the water they use every day, they mostly are considering freshwater. Of all the water withdrawn in 2005 for the Nation, 349,000 million gallons per day (Mgal/d) or 85 percent, was freshwater. If water withdrawn by the thermoelectric-power industry is excluded, then over 99 percent of total withdrawals was freshwater.
About 77 percent of the freshwater used in the United States in 2005 came from surface-water sources. The other 23 percent came from groundwater.
For 2005, most of the fresh surface-water withdrawals, 41 percent, was used in the thermoelectric-power industry to cool electricity-generating equipment. Water used in this manner is most often returned to the water body from which it came. That is why the more significant use of surface water is for irrigation, which used about 31 percent of all fresh surface water; ignoring thermoelectric-power withdrawals, irrigation accounted for about 63 percent of the Nation's surface-water withdrawals. Public supply and industrial were the next largest users of surface water.
Water is everywhere, which is fortunate for all of humanity, as water is essential for life. Even though water is not always available in the needed quantity and quality for all people everywhere, people have learned to get and use water for all of their water needs, from drinking, cleaning, irrigating crops, producing electricity, and for just having fun.
• Water Science School HOME • Water Science Q&As •
Water Use Questions & Answers
Here are some questions and answers about water use that may interest you:
Where does our household water come from?
The U.S. Geological Survey (USGS) compiles national water-use information every 5 years, with the last compilation done in 2015. As far as where all the water is from that we use in our homes, it is from either a groundwater source, such as a well, or from a surface-water source, such a river, lake, or reservoir.In the U.S. in 2015, about 283 million of the 325 million people in the United States got their home water delivered by a public supplier, such as the county water department. At other homes, mainly in more rural areas, people provide water for themselves from sources such as a well, a cistern, a pond, or a stream. It is common that groundwater wells provide water for these users, with almost 98% of water coming from fresh groundwater sources.
How much water do I use at home each day?
Estimates vary, but, on average, each person uses about 80-100 gallons of water per day, for indoor home uses. Are you surprised that the largest use of household water is to flush the toilet, and after that, to take showers and baths? That is why, in these days of water conservation, we are starting to see toilets and showers that use less water than before.
Many local governments now have laws that specify that water faucets, toilets, and showers only allow a certain amount of water flow per minute. Water agencies in some areas, such as here in Atlanta, Georgia, offer rebates if you install a water-efficient toilet. Yes, these toilets really do use a lot less water. For your kitchen and bathroom faucets, if you look real close at the head of a faucet, you might see something like "1.0 gpm", which means that the faucet head will allow water to flow at a maximum of 1.0 gallons per minute.
How is sewage and wastewater treated?
Different treatment is used depending on the source of your water. Groundwater taken from wells has been filtered through rocks, so it is usually quite free of particles. It can still contain chemicals and organic matter that must be taken out, though.
If your water comes from a surface-water source, such as a river or lake, some work must be done to get rid of particulate matter. Often water is withdrawn and pumped into holding ponds or containers, where solids and particles can settle to the bottom. Possibly filters and sand beds are used to screen out particulate matter, and at a minimum, chlorine is added to kill dangerous bacteria and microorganisms.
Why does my water smell like rotten eggs?
You would know it if you had this problem! A frequent cause of musty, earthy odors in water is naturally occurring organic compounds derived from the decay of plant material in lakes and reservoirs. In some parts of the country, drinking water can contain the chemical hydrogen sulfide gas, which smells just like rotten eggs. This can occur when water comes into contact with organic matter or with some minerals, such as pyrite. The situation mostly occurs as groundwater filters through organic material or rocks.
Water containing hydrogen sulfide can have an odor that is objectionable (and the water may taste really bad), but generally the water is not harmful to health. However, odors can be caused by other constituents as well, so you may want to call your local Health Department and mention the odor to them. The best way to find out what is in your water is to have the water tested by a state certified laboratory. A list of these labs is available from the U.S. Environmental Protection Agency State Certification Program. Your local county Extension office may also offer water testing.
Where does our home wastewater go?
Water leaving our homes generally goes either into a septic tank in the back yard where it seeps back into the ground, or is sent to a wastewater-treatment plant through a sewer system.
Different treatment is used depending on the type of water coming into the plant and the water-quality requirements of water leaving the plant. Often the first stages of water treatment are purely physical methods, such as letting solid particles settle to the bottom of a holding tank and filtering the water through sand or other fine particulate matter. Filters are used to screen out large particles, and at a minimum, chlorine is added to kill dangerous bacteria and microorganisms.
A typical set of steps to treat water:
- Odor control: Chemicals can help keep down foul odors
- Screening: Move water through screens to separate larger solids and trash
- Primary treatment: Move water into large tanks and allow solid material to settle at the surface. Scrape material off and dispose of it
- Aeration: Stir up the water to get it to release gasses, and pump air through the water to allow bacteria to act on organic matter to help it decay.
- Remove sludge: Solid material settles to the bottom and removed
- More filtration: Filter water through sand, for example, to reduce bacteria, odors, iron, and other solids.
- "Digest" the solid material: Hold and heat the solid material to break it down to nutrient-rich biosolids and methane gas
- Disinfection: Water is treated with chlorine to kill bacteria
Wastewater treatment plants can treat sewage and create water that can be used for other purposes (relaimed wastewater).
Some systems have additional water treatment that use biologic processes to remove organics, nitrogen, and phosphorus, a membrane tank to remove bacteria and suspended solids, ultraviolet disinfection to render viruses inactive, and aeration to raise the oxygen level (needed by fish living in the river where the treated wastewater is dumped after cleansing).
How much water falls during a storm?
In other words, when I have a big storm over my house, just how much rain am I getting? Let's say your house sits on a one-half acre lot. And let's say you get a storm that drops 1 inch of rain. You've just received 13,577 gallons of water on your yard. A big bath holds about 40 gallons of water, so if you could save that inch of water that fell you could take a daily bath for 339 days! Let's expand that to a city. Atlanta, Georgia has corporate boundaries that cover about 84,100 acres (U.S. Census Bureau). A 1-inch rainstorm deposits 27,154 gallons on one acre, so during this storm Atlanta receives 2.28 billion gallons of water.
In this era of water conservation, many homeowners are putting "rain barrels" around their homes to collect rainfall runoff. Essentially, this is just a large bucket to collects water coming off of the roof and down the gutters and downspouts. The water is then used to water gardens and plants. Can you get enough water out of the gutter to make it worthwhile? The answer is definitely "yes". A typical outdoor trash can holds 32 gallons. If you capture the rainfall runoff from a storm that just produces 1/10th of an inch of rain onto a 20 by 30 foot roof, you end up with a full 32-gallon container full of water, with 5 gallons left over.
You can use our handy "How much water falls during a storm" calculator to find out how much water falls during a rainstorm for a chosen sized area.
Does a little leak in my house really waste water?
It's not the little leak that wastes water—it is the little leak that keeps on leaking that wastes water. And the fact that the leak is so little means that maybe you ignore it. So, how can a little leak turn into a big waste? Many of our toilets have a constant leak—somewhere around 22 gallons per day. This translates into about 8,000 gallons per year of wasted water, water that could be saved. Or think of a leaky water line coming into your house. If it leaks 1 gallon of water every 10 minutes that means that you are losing (and paying for) 144 gallons per day, or 52,560 gallons per year.
There is no scientific definition of the volume of a faucet drip, but after measuring a number of kitchen and bathroom sink faucets, the volume seems to be between 1/5th and 1/3rd of a milliliter (mL). Drips from bathroom tubs come in a bit more, though, at about 1/2 mL. So, we are going to use 1/4 mL as the volume of a kitchen faucet drip. So, by these drip estimates:
- One gallon: 15,140 drips
- One liter: 4,000 drips
Looking at it this way, it seems like that drop of water down the drain is pretty insignificant. But, if you use our handy Drip Calculator, you can see that all those drops flowing in "real time" can really add up to a flood of wasted water.
What makes a groundwater well go dry?
A well is said to have gone dry when water levels drop below a pump intake. This does not mean that a dry well will never have water in it again, as the water level may come back through time as aquifer recharge from precipitation seepage increases and/or pumping of the aquifer is lessened. It is true that all the water in the ground comes from infiltration of precipitation from above, but the geology of the underground rock determines the infiltration and movement characteristics of the water that is in the ground.
The water level in a well depends on a number of things:
- Depth of the well
- Type (confined or unconfined) of aquifer the well taps
- Amount and rate of pumping that occurs in the aquifer
- Permeability and porosity of the underground rock
- Amount of recharge occurring from precipitation or artificial recharge
Wells in unconfined water table aquifers are more directly influenced by the lack of rain than those in deeper confined aquifers. A deep well in a confined aquifer in an area with minimal pumping is less likely to go dry than a shallow, water-table well.
How important is groundwater?
Groundwater, which is in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 33 percent of the water that county and city water departments supply to households and businesses (public supply). It provides drinking water for more than 90 percent of the rural population who do not get their water delivered to them from a county/city water department or private water company. Even some major cities, such as San Antonio, Texas, rely solely on groundwater for all their needs. In 2015, about 48 percent of the water used for irrigation comes from groundwater. Withdrawals of groundwater are expected to rise as the population increases and available sites for surface reservoirs become more limited.
About 29 percent of the freshwater used in the United States in 2015 came from groundwater sources. The other 71 percent came from surface water. Groundwater is an especially important natural resource in those parts of the country that don't have ample surface-water sources, such as the arid West. It often takes more work and costs more to access groundwater as opposed to surface water, but where there is little water on the land surface, groundwater can supply the water needs of people.
Is salt water useful?
In today's world we are all more aware of the need to conserve freshwater. With the ever-growing demand for water by growing populations worldwide, it makes sense to try to find more uses for the abundant saline water (salt water) supplies that exist, mainly in the oceans. You may not be able to use saline water to water you garden full of delicious rutabagas, broccoli, and spinach, but saline water does have some valuable uses. As these pie charts of the Nation's water use show, about 13 percent of all water used in the United States in 2015 was saline. Almost all saline withdrawals, over 95 percent, was used by the thermoelectric-power industry to cool electricity-generating equipment. About five percent of the Nation's saline water was used for mining and industrial purposes.
Perhaps one of the most important uses of saline water, and something that will become more important in the future, is that it provides a ample supply of water that can be desalinated and turned into fresh water. The processes to desalinate water is costly, though, so as costs come down it will be used more and more.
Which states use the most water?
More than one-fourth of the total water used in the United States in 2015 was withdrawn in California, Texas, Idaho, and Florida. California accounted for 9 percent of all withdrawals in the United States in 2015. Nearly three-fourths of the freshwater withdrawn in California was for irrigation, and 98 percent of saline water withdrawn was for thermoelectric-power generation.
In 2015, more than 50 percent of the total withdrawals in the United States were accounted for by 12 States: California, Texas, Idaho, Florida, Arkansas, New York, Illinois, Colorado, North Carolina, Michigan, Montana, and Nebraska.
https://labs.waterdata.usgs.gov/visualizations/water-use/index.html
What is most of the freshwater in the U.S. used for?
The water in the Nation's rivers, streams, creeks, lakes, reservoirs, and in underground aquifers are vitally important to our everyday life. Although saline water is used for some purposes, mainly to produce electricity, when people think of the water they use every day, they mostly are considering freshwater. Of all the water withdrawn in 2005 for the Nation, 349,000 million gallons per day (Mgal/d) or 85 percent, was freshwater. If water withdrawn by the thermoelectric-power industry is excluded, then over 99 percent of total withdrawals was freshwater.
About 77 percent of the freshwater used in the United States in 2005 came from surface-water sources. The other 23 percent came from groundwater.
For 2005, most of the fresh surface-water withdrawals, 41 percent, was used in the thermoelectric-power industry to cool electricity-generating equipment. Water used in this manner is most often returned to the water body from which it came. That is why the more significant use of surface water is for irrigation, which used about 31 percent of all fresh surface water; ignoring thermoelectric-power withdrawals, irrigation accounted for about 63 percent of the Nation's surface-water withdrawals. Public supply and industrial were the next largest users of surface water.