California Water Supply
California Water
Future Water Supply Reliability
Although water seems limitless and is for the most part taken for granted, it is not an absolute certainty that where settlement occurs, water will follow. This fact has not escaped water experts and decision-makers, who realize the many competing needs for a precious resource that has no substitute.
As California heads toward a future of further population growth, a number of factors have to be considered as agencies look to accommodate the increasing demand. As California heads toward a future of further population growth, a number of factors have to be considered as agencies look to accommodate the increasing demand. In addition to the growth itself, other variables such as climate change, environmental conflicts and aging infrastructure could affect the future reliability of the state's water supplies. Recognizing the era of big projects has past, state and local officials have turned to a new supply paradigm that emphasizes regionally developed supply alternatives and the need for innovative approaches that accentuate the opportunities offered by conjunctive management.
This issue is discussed in DWR's update to the State Water Plan, which can be viewed at www.waterplan.water.ca.gov.
The process is understandably challenging and requires at least as much energy, enthusiasm and vision that enabled pioneers to tap the water supply potential of this vast state.
Learn About Your Watershed
Visit this U.S. EPA web site to learn more about the surface water resources in your region, http://cfpub.epa.gov/surf/locate/index.cfm
The Basics
Water is essential for life as we know it. Water grows our food, powers turbines for electricity and serves as the lifeblood of industry. Water nurtures our landscapes and provides habitat for wildlife. It is estimated between 70 and 75 percent of the Earth's surface is covered with water, more than 96 percent of which is too salty for most human uses.
Today, significant technological developments in monitoring, assessing and treating water ensure a drinking water supply of high quality for most people.
Today, substantial water development projects have occurred in every region of the state, from the Bay Area to Los Angeles to the burgeoning Inland Empire. Thus, residential, commercial and municipal users are drawing more of their supply from a mixture of imported and locally developed sources.
From the earliest days of U.S. history, finding and maintaining a clean water supply for drinking and other uses has been a high priority. Today, significant technological developments in monitoring, assessing and treating water ensure a drinking water supply of high quality for most people. Because of water's long history, life-supporting properties and future use, it needs to be protected from pollutants - whether natural or manmade. Ensuring a supply that sustains life for future generations has become part of the social contract.
Where a community's water comes from depends largely on the foresight and planning of its founders and the historic use of local lands and water sources. Some communities, such as Sacramento, claimed water rights early in their history in order to assure themselves an adequate supply far into the future. Other communities do not have access to adequate supplies of good quality local water to meet their needs. Some of these communities import water, sometimes over great distances, from state or federal water projects or large water districts.
The Water Cycle
Water is continually moving around, through and above the Earth. It moves as water vapor, liquid water and ice. It is constantly changing its form. The movement of water is referred to as the hydrologic or water cycle. Precipitation, evaporation/transpiration and runoff (surface runoff and subsurface infiltration) are the primary phases in the cycle.
Surface Water
Groundwater
Groundwater is the portion of water beneath the Earth's surface that can be collected with wells or which flows naturally to the surface via seepage or springs. California's enormous groundwater reservoirs are estimated to hold about 20 times the amount of water that is stored behind all the dams in the state. Groundwater doesn't exist in underground lakes but in the pores and spaces between alluvial materials (sand, gravel, silt or clay) in water-bearing formations called aquifers.
Acre-foot
Water is commonly measured by the acre-foot. One acre foot equals 325,851 gallons. Put another way, an acre-foot of water is enough to flood a football field - which is roughly an acre in size - 1 foot deep. The average California household uses between one-half and one acre-foot of water per year for indoor and outdoor each year.
How is Water Distributed?
Public agencies and private water developers have built nearly 1,400 reservoirs in California to capture seasonal runoff, protect against floods and allocate water supplies throughout the year. These reservoirs hold about 42 million acre-feet of water when full.
Most of the state's rainfall occurs from December through April, but the greatest demand for water is during the dry summer months.
Before 1900, water development in California was principally undertaken by individuals and private companies. As the population and economic activity of the state grew, cities, irrigation districts, public utilities and large municipal agencies took on the responsibility for developing water supplies for their jurisdictions. Over time, large distribution networks were developed to pipe treated surface and groundwater to homes, businesses, parks, schools and other facilities.
How is Drinking Water Treated?
Nearly a century ago, controlling water-borne disease was the main treatment goal of water providers. Today, water agencies large and small provide their customers with the highest quality drinking water in the world. Before disinfection became a common practice, widespread outbreaks of cholera and typhoid were frequent throughout the United States. These diseases are still common in less developed countries, but largely disappeared in the United States when chlorine and filtration became widely used 80 years ago.
Before disinfection became a common practice, widespread outbreaks of cholera and typhoid were frequent throughout the United States.
Water treatment technology must deal with a number of potential perils resulting from the movement of water from its source to our tap. Mountain springs might flow through sulfur, zinc or arsenic-laden formations. Groundwater can pick up contamination from fertilizers, septic tanks, mine drainage, naturally occurring minerals, industrial chemicals and metals such as arsenic and chromium. Rivers and streams sometimes carry harmful microorganisms from animals or humans, presenting a risk of disease. Storm drains can carry polluted runoff from cities into rivers and streams.
U.S. drinking water supplies are heavily regulated. Public and private water suppliers operating treatment systems today have methods to control nearly all of the properties found in water: hardness, acidity and alkalinity, color, turbidity, taste and odor, as well as the biological and organic chemical characteristics. Large water suppliers have their own laboratories to test water while smaller agencies use commercial labs.
In some systems, fluoride is added to reduce tooth decay. California law requires fluoridation of water in systems with 10,000 or more connections if outside funding is provided. According to the state, 30 percent of all public water providers in California fluoridate their water.
The treatment of groundwater varies from community to community, and even from well to well within a city depending on contaminants in the water. The water may be treated as it is pumped from the ground to remove certain contaminants or it may be chlorinated if there is concern of bacterial or parasitic infection.
The driving force behind the development of drinking water standards and regulations is the protection of public health. Many laws have been adopted concerning water quality standards, going as far back as the Interstate Quarantine Act of 1893, which sought to control the introduction of communicable diseases from other countries. The first drinking water regulations prohibited the use of a common drinking cup on trains.
The first federal drinking water standard, adopted in 1914, was limited to bacteriological quality of water and not physical and chemical requirements. By 1925, cities were using filtration, chlorination or both and had little difficulty complying with the coliform standard. Eventually, limits were established for lead, copper, zinc and excessive soluble mineral substances. In 1941, an advisory committee of federal agency representatives, scientific associations and at-large members was formed to revise drinking water regulations. In 1942, the committee agreed on significant initiatives such as required bacteriological examinations in water distribution systems and maximum concentrations for lead, fluoride, arsenic and selenium. Twenty years later, the U.S. Public Health Service developed drinking water standards that were used by California.
During the following decades, federal water pollution control efforts focused on physical, biological, chemical and industrial waste. Passed by Congress in 1974, the Safe Drinking Water Act (SDWA) regulates drinking water quality in the United States. Under the SDWA, the U.S. Environmental protection Agency (EPA) can delegate implementation of drinking water regulations to states that have developed programs at least as stringent as the federal one. Such states, including California, have primary enforcement responsibility for administering their own programs.
Under the SDWA, public water systems are required to conduct testing on a regular basis. Monthly monitoring for microbial contaminants is required for both surface water and groundwater systems, while organic chemical monitoring must be conducted annually by surface systems and every three years by groundwater systems.
Contaminants fell into several categories: those that occur naturally, such as arsenic and uranium, those that are manmade, such as solvents or pesticides; and those that derive primarily from the materials used in supplying water, most notably disinfection byproducts (DBPs). The byproducts emerge from the treatment process when chlorine reacts with naturally occurring organic compounds found in the water supply. Public health experts note the possible risks from DBPs are limited compared to inadequate disinfection of drinking water.
EPA established pollutant-specific minimum testing schedules for public water systems. If a problem is detected, there are immediate retesting requirements that go into effect and strict instructions for how the system informs the public about the problem. Until the system can reliably demonstrate that it is free of problems, the retesting is continued.
Private Wells
When water is provided by a private well, periodic testing of its water is recommended but not mandated. Owners of private wells should use only laboratories certified by the California Department of Heath Services to conduct an analysis. Private wells fall outside federal and state regulation because they are on private land and not covered by the SDWA. They also are not subject to the same periodic testing and monitoring requirements as public water systems. There are more than 600,000 private wells in California.
Experts recommend having private well water tested at least once a year for coliform bacteria.
When it comes to toxic substances, more detailed - and expensive - testing can be done. Testing for minerals can cost from $130 to $200. Testing for organic "priority pollutants" may cost an additional $200 to $300. Testing for all regulated chemicals require even more extensive tests and can cost several thousand dollars per sample. If a contaminant is detected, the results will include the concentration of the contaminant and an indication of whether this concentration exceeds a drinking water quality standard. If a standard is exceeded, consumers are advised to retest the water supply immediately and contact the public health department for assistance.
Sometimes it is not necessary to check for the full range of pollutants. The health department probably is aware of metals or other possible contaminants of concern in the vicinity. County and state health departments keep records on well trouble spots and can advise whether any substances of concern have been found in other area wells nearby. However, water experts caution that different wells may not be drilled to the same depth or obtain water from the same geologic formation.
Information on well water quality is also available from the State Water Resources Control Board. The Groundwater Ambient Monitoring and Assessment (GAMA) Domestic Well Project samples private domestic wells for chemicals commonly found in well water. The areas sampled are chosen based upon existing knowledge of water quality and land use, in coordination with county environmental health agencies. The state incurs the costs of sampling, and the test results are provided to well owners who volunteered to have their well sampled. More information about the GAMA Domestic Well Project is available at http://www.waterboards.ca.gov/water_issues/programs/gama/domestic_well.shtml
In addition, the GAMA website also provides detailed information to private domestic well owners with concerns about their well water quality. The webpage to help you find important information about domestic wells is available at http://www.waterboards.ca.gov/gama/wq_privatewells.shtml
Small Water Systems
In California, the Department of Health Services (DHS) is responsible for regulating drinking water and for monitoring approximately 7,500 public water systems to assure the delivery of safe drinking water to all Californians. For small systems with 200 or fewer connections, the DHS' Drinking Water Field Operations Branches (DWFOB) work with county health departments, planning departments, and boards of supervisors that have primary regulatory oversight.
Many small systems are located in low-income communities, making it more difficult to raise funds for improvement.
Many small systems are located in low-income communities, making it more difficult to raise funds for improvement. The lack of financial resources means small water providers often use volunteered for operation and maintenance. The SDWA amendments established financial assistance programs for infrastructure and training, but the effort is limited by the large number of entities in need of assistance and the extent of the resources provided by EPA. For more information, visit www.epa.gov/safewater/smallsys/ssinfo.htm
Pollution Prevention
Pollution that impacts water quality is divided into point and nonpoint sources. Point source pollution is discharged from a known source, such as a wastewater treatment plant or a factory. Point sources are monitored and regulated to control discharges.
The leading cause of water quality problems is nonpoint source pollution, the accumulation of runoff from city streets, construction sites and agricultural fields, spills and abandoned mines.
It was once thought that polluted water would be naturally filtered as it seeped underground, but that is not the case. Many industrial chemicals are highly persistent and do not break down in soil. Consequently, more technologically advanced testing techniques are necessary to detect contamination. The full extent of groundwater contamination is not known, but the number of threats has increased, forcing the closure of thousands of wells.
Nonpoint sources are difficult to regulate because of their diffuse nature and so are dealt with through management measures that stress prevention and cost-effective, low-tech solutions.
Because of the collective impact of multiple pollutants on drinking water supplies, recreation, fisheries and wildlife, officials say the solution to the problem lies in educating people that they all have a part to play in minimizing the amount of pollutants that originate in a watershed. Among other things, this includes carefully following directions when applying lawn fertilizers, curbing pet waste and ensuring motor oil and other harmful chemicals are kept out of storm drains. Information about steps you can take to reduce runoff can be found at this website, http://www.waterboards.ca.gov/nps/index.html
Stretching the Water Supply
Even as the available supply of water in California remains fixed, the state's increasing demand means water suppliers and water users must do all they can to squeeze the most use from each precious drop of water. This necessity becomes even more evident in years when drought conditions exist and the water supply is precariously balanced between urban, agricultural and environmental demands.
Water conservation is an essential tool to stretch the water supply - or more accurately, to use the existing supply more efficiently.
Urban water suppliers have developed and implemented water conservation practices known as Best Management Practices (BMPs). These include the installation of water-saving plumbing fixtures and water meters on all new construction, public information programs, municipal landscape water conservation requirements and financial incentives to reduce water use. DWR estimates that following urban BMPs could reduce annual water demand by 900,000 acre-feet by 2020.
Conjunctive Use
Conjunctive use is the coordinated management of surface water and groundwater supplies to maximize the yield of the overall water resource. An active form of conjunctive use utilizes artificial recharge, where surface water is intentionally percolated or injected into aquifers for later use. A passive method is to simply rely on surface water in wet years and use groundwater in dry years. More than 65 water agencies in the state operate groundwater recharge programs. The success of many of these programs, however, depends on purchasing available surface water from other users.
Conjunctive use is becoming a key part of the state's overall water management strategy in terms of coping with a growing population.
Desalination
The process of removing dissolved minerals, such as salt, from sea water and brackish groundwater is gaining favor as a method of augmenting urban water supplies. Estimates are that seawater and brackish water desalination will increase by 10 to 20 percent in the next decade, with existing and envisioned operations eventually generating an estimated 700 million gallons per day. About two dozen seawater desalination plants are proposed along the California coast.
Estimates are that seawater and brackish water desalination will increase by 10 to 20 percent in the next decade.
Water Recycling
Water recycling (or water reclamation) involves treating municipal wastewater to remove sediments and impurities for reuse. As demand for water increases, techniques for recycling and reuse of water become more attractive. Using recycled water reduces reliance on increasingly scarce and expensive surface water and can minimize groundwater overdraft (extracting more water than is replenished.) Additionally, as a direct result of water recycling, discharges of treated wastewater into rivers and the ocean are reduced. Recycled water also has the advantage of being a local, drought-resistant supply - a key selling point in semi-arid states like California.
Water recycling and reuse plays an important role in California's overall water supply and management program.
Future Water Supply Reliability
Although water seems limitless and is for the most part taken for granted, it is not an absolute certainty that where settlement occurs, water will follow. This fact has not escaped water experts and decision-makers, who realize the many competing needs for a precious resource that has no substitute.
As California heads toward a future of further population growth, a number of factors have to be considered as agencies look to accommodate the increasing demand.
This issue is discussed in DWR's update to the State Water Plan, which can be viewed at www.waterplan.water.ca.gov.
The process is understandably challenging and requires at least as much energy, enthusiasm and vision that enabled pioneers to tap the water supply potential of this vast state.
Learn About Your Watershed
Visit this U.S. EPA web site to learn more about the surface water resources in your region, http://cfpub.epa.gov/surf/locate/index.cfm
For centuries, people have relied on rainwater harvesting to supply water for household, landscape, livestock, and agricultural uses. Before the advent of large centralized water supply systems, rainwater was collected from roofs and stored on site in tanks known as cisterns. With the development of large, reliable water treatment and distribution systems and more affordable well drilling equipment, rain harvesting was all but forgotten, even though it offered a source of pure, soft, low-sodium water.
A renewed interest in this time-honored approach of collecting water has emerged in California and elsewhere because of water shortage, escalating environmental and economic costs of providing water by centralized water systems or by well drilling. The health benefits of rainwater, and potential cost savings associated with rainwater collection systems have further spurred this interest.
About greywater reuse
Greywater is water from your bathroom sinks, showers, tubs, and washing machines. It is not water that has come into contact with feces, either from the toilet or from washing diapers.
Greywater may contain traces of dirt, food, grease, hair, and certain household cleaning products. While greywater may look “dirty,” it is a safe and even beneficial source of irrigation water in a yard. If released into rivers, lakes, or estuaries, the nutrients in greywater become pollutants, but to plants, they are valuable fertilizer. Aside from the obvious benefits of saving water (and money on your water bill), reusing your greywater keeps it out of the sewer or septic system, thereby reducing the chance that it will pollute local water bodies. Reusing greywater for irrigation reconnects urban residents and our backyard gardens to the natural water cycle.
The easiest way to use greywater is to pipe it directly outside and use it to water ornamental plants or fruit trees. Greywater can be used directly on vegetables as long as it doesn't touch edible parts of the plants. In any greywater system, it is essential to put nothing toxic down the drain--no bleach, no dye, no bath salts, no cleanser, no shampoo with unpronounceable ingredients, and no products containing boron, which is toxic to plants. It is crucial to use all-natural, biodegradable soaps whose ingredients do not harm plants. Most powdered detergent, and some liquid detergent, is sodium based, but sodium can keep seeds from sprouting and destroy the structure of clay soils. Chose salt-free liquid soaps. While you're at it, watch out for your own health: "natural" body products often contain substances toxic to humans, including parabens, stearalkonium chloride, phenoxyethanol, polyethelene glycol (PEG), and synthetic fragrances. (to learn more about what’s in your products, go to the Cosmetic Database and see how they rate for toxicity). Read our recommendations for soaps and products here.
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