The Early Years: Siding with Sanitation
The early days of the water business in pioneer Denver were hardly glamorous, but at least the city came down on the side of sanitation. Shortly after City Ditch was completed in 1867, the city became alarmed that pigs running loose were contaminating the ditch, presenting the threat of cholera. Water treatment apparently not an immediate option, city council banished the animals from town by eliminating the city’s power to license hogs.
City Ditch, extending from above Littleton on the South Platte River to Capitol Hill,
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| Construction of City Ditch, late 1860's. For a larger view in a separate window, click here. |
Though exposed waterways posed a problem, Denver Water’s predecessors treated drinking water from inception, always employing some type of granular filtration, however primitive. The private companies cropping up beginning in 1870 laid mains to deliver drinking water, slowly replacing wells with diverted river water. The first infiltration galleries were buried along Cherry Creek in 1886 and at the Platte Canyon Filtration Plant (Kassler) in 1889. The first "rapid sand" mechanical filters were built in 1892 at the Willard Filter Plant, and the first chlorination feeds – effective in preventing cholera and typhoid epidemics – were installed at all filter plants in 1906.
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| City Ditch was just an open canal that fed raw water into miles and miles of smaller lateral ditches intended espressly for irrigation and perhaps fire control. But sanitation issues were raised, and confronted with a serious menace to public health, the city began pipelining the ditch in the late 1880s. |
The Mission: Fresh, Safe Water and Lots of It
A tradition of excellence was already established in 1918 when Denver’s voters chose to create an independent, municipal water department to serve a growing city. Providing clean, safe drinking water always has been as important to the agency as producing ample supplies.
We keep an eye on it every step of the way, monitoring mountain resources and carefully filtering and treating the water before it reaches your tap. Throughout the process, it is tested many times. Here’s a look at how Denver Water continues to serve you with healthy, dependable drinking water in a period when we can search for ever smaller concentrations of contaminants. Our efforts reflect society’s concern with health and a growing awareness of vulnerable populations within our society.
High-Quality Runoff
Denver’s drinking water comes from rivers, lakes and streams fed by mountain snow runoff, and the city is the first major user in line for these supplies. The water comes entirely from surface sources over a watershed that covers 3,100 square miles on both sides of the Continental Divide. The farthest reaches of this system are more than 105 miles away, and the water is diverted and delivered by gravity to metro treatment plants through a complex system of streams, canals, tunnels and conduits.
Even though the water originates in pristine alpine areas, our operations include watershed protection. Recently, Denver Water has begun programs with state and federal agencies, local governments and businesses to minimize impact of growth and development. On another front, Denver Water employees – caretakers and their families – live and work throughout our watershed to maintain continual surveillance of the water supply. Even though these areas are relatively remote with low populations, our caretakers and water quality specialists are on the watch for unusual occurrences and are prepared for problems or emergencies.
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| Sources of Denver's water. For a larger view in a separate window, click here. |
Sources of Denver’s water are the South Platte River and its tributaries, the streams that feed Dillon Reservoir, and the creeks and canals above the Fraser River near Winter Park. Mountain water is stored in five reservoirs – Antero, Eleven Mile, Cheesman, Dillon and Gross – before it is sent to three treatment plants in the city. Prior to treatment, the water flows to three "terminal" reservoirs that are off limits to the public to further ensure the quality of the water. During the drought, Denver Water also has drawn water from Chatfield Reservoir and Bear Creek.
At key points along the way, Denver Water analysts collect and test samples, checking quality and identifying potential problems long before water reaches the treatment plants.
For "exchange" purposes, Denver Water also operates Williams Fork Reservoir near Parshall and stores water in Wolford Mountain Reservoir near Kremmling, but the supplies in these facilities do not reach the city.
Water Treatment Process
| 1 The treatment process consists of five steps – coagulation, sedimentation, filtration, corrosion control and disinfection. First, raw water from terminal reservoirs is drawn into mixing basins at our treatment plants, where we add alum and polymer ... | 2 ... that causes small particles to adhere to one another, making them heavy enough to settle into a basin from which sediment is removed. The water is then filtered through layers of fine, granulated material, either sand, coal or both, depending on the treatment plant ... | ||
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| 4 .... Denver Water carefully monitors the amount of disinfectant added to maintain quality of water at the farthest reaches of the system. Fluoride occurs naturally but is also added to treated water, and pH is maintained by adding alkaline substances to reduce corrosion in the distribution system and your home or business. | 3 ... As smaller, suspended particles are removed, turbidity diminishes and clear water emerges. Finally, as protection against any bacteria and viruses that might remain, disinfectant is added before the water flows to underground reservoirs throughout the metro distribution system and into your home or business ... | ||
Every Drop: Clean and Safe
On a hot summer day, Denver Water’s three treatment plants can collectively transform raw mountain runoff into 715 million gallons of drinking water for 1.2 million customers in the metropolitan area. Every drop must be clean and safe. To do this, the water department’s plants at Foothills, Marston and Moffat are constantly maintained, evaluated and upgraded to stay abreast of advancements in technology, health science and governmental regulations. Plant operators must meet rigorous education and experience requirements as well as possess state certification. They provide coverage 24 hours a day, seven days a week, to ensure a constant supply of safe drinking water.
The treatment process consists of five steps – coagulation, sedimentation, filtration, corrosion control and disinfection. First, raw water from terminal reservoirs is drawn into mixing basins at our treatment plants, where alum and polymer are added, causing small particles to adhere to one another, making them heavy enough to settle into a basin from which sediment is removed.
Clarified water is then filtered through layers of fine, granulated material that's either sand, coal or both, depending on the treatment plant. As smaller, suspended particles are removed, the slight cloudiness disappears and clear water emerges. Finally, as protection against any bacteria and viruses that might remain, a chlorine-based disinfectant is added before the water flows to underground reservoirs throughout the metro distribution system and into your home or business. Denver Water carefully monitors the amount of disinfectant, adding the lowest quantity necessary to protect the water’s safety without compromising taste. Disinfection is vital for a clean, safe water supply. Chlorination of drinking water has saved more lives than any medicine in history, according to the U.S. Centers for Disease Control.
Fluoride occurs naturally, but also is added at levels recommended by the state health department. The pH of the water is adjusted by adding sodium hydroxide to reduce corrosion in the distribution system and your home or business.
Throughout the process, treatment plant operators and water quality specialists collect and analyze samples to guarantee effectiveness of each treatment step.
Denver Water continues to evaluate alternate technologies and upgrade its treatment plants to ensure that current and future regulations are met. Technologies, such as ultraviolet light disinfection, are being studied as an addition to the treatment process. Denver Water is committed to not only meeting requirements of the water quality regulations, but to providing water that is even better than regulations require.
High Quality in the Distribution System
After treatment, drinking water is fed by both gravity and pumps to an enclosed system of underground, clear-water reservoirs scattered throughout the metro area and then to your home or business.
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- Any time a Denver Water crew excavates a pipe — to repair a break or for routine maintenance – or lays a new one, the pipe and any other repair parts are disinfected. Before the pipe is returned to service, it is flushed and water samples are analyzed to assure the high quality of the water.
- Throughout Denver Water’s service area, water samples are taken regularly from more than 200 locations across the region by water quality investigators to make sure water meets precise safety standards.
- Through an intricate, computerized network of more than 600 data, alarm and control points, state-certified operators monitor and control the entire water system 24 hours a day. This system includes a network of water quality sensors that provide continuous surveillance of your water.
- The city’s underground reservoirs — which provide a constant supply of water even when demand fluctuates greatly – are inspected, drained, cleaned and disinfected at least yearly.
Testing to the Limit
Key to Denver Water’s quality assurance program are the 26 highly trained scientists and technicians at the state-certified Marston Water Quality Lab.
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Development of increasingly sensitive scientific instruments and sophisticated analytical techniques makes it possible to analyze water samples more precisely and detect contaminants in more minute quantities than were previously imagined. Just a few years ago, tests were preformed at one part per million, or one drop in 55 gallons of water. Today, measurements are 1,000 times more sensitive – in fractions of one part per billion. A part per billion is the equivalent of one drop of water in 55,000 gallons.
A Clean Record
All water naturally contains a variety of dissolved mineral and organic substances. The presence of these substances doesn’t necessarily indicate a health risk. In fact, some minerals are beneficial. Federal and state drinking water standards establish limits, called maximum contaminant levels, for substances that may affect health or aesthetic qualities of water.
The Safe Drinking Water Act authorizes the federal government to establish such limits as well as monitoring requirements. As technological capabilities expand, making it possible to examine increasingly minute particles and identify new contaminants, more stringent requirements continue to be established. On the contaminants "watch list" are pesticides, metals, bacteria and radioactive substances.
The water department has conducted tests of its drinking water since it was established in 1918, and our findings always have been available to the public. Since 1996, we have been publishing an annual water quality report summarizing our quality assurance program and listing the few substances detected, none of which breeched health standards.
Water Quality Reports
Denver Water publishes an annual comprehensive Water Quality Report which summarizes where our water comes from, what's in it, and how we treat, protect, and deliver drinking water. This consumer report contains a "Treated Water Quality Roundup" in which the department's test results are compared with feneral and state regulations. Our record remains unblemished. The Consumer Confidence Report is mailed to all of Denver Water's customers eash April and May. Denver Water also publishes a Treated Water Quality Report annually, with more details on water treatment and quality, as well as other pamphlets and brochures on water quality. Many of these publications can be found reproduced online. Go to the denverwater.org Water Quality main page for a current list.
Recycled Water
Denver
 | For more information about Denver Water's recycled water program, click here. |
The reclaimed water isn’t up to drinking-water standards, but is treated to a high, nonpotable quality suited for irrigation, industrial applications, lakes in parks and wildlife preserves. It’s safe for incidental body contact for both humans and animals. Recycled water has been used elsewhere in Colorado and the United States for many years to irrigate parks, golf courses and crops without a reported illness.
Recycled water is delivered to irrigators and industries through a separate system of purple pipes. There is no direct connection between recycled water and drinking-water systems, and recycled water isn't available for residential irrigation. Like potable water, recycled water also is subjected to quality assurance monitoring and laboratory analyses. Tests conducted daily by the Water Quality Lab and plant operators during treatment and in the system are available to the public.
Recycled water began reaching customers in central Denver early in 2004. When completed in 2011, the system will recycle as much as 17,660 acre feet of water annually. At full capacity, the facility will treat up to 45 million gallons daily from the Metro Wastewater District's treatment plant.
Water Softeners
Some of Denver’s water is considered moderately hard because it contains calcium and magnesium, both of which occur naturally in our source water and are known to be harmless. With regard to drinking water safety, there is no difference between properly treated hard water and properly treated soft water. However, hard water makes washing more difficult because the minerals mix with soap, diminishing suds. Denver’s water hardness ranges from two to seven grains per gallon, which fluctuates seasonally and by source.
Water softeners remove most of the calcium and magnesium. Many softeners replace the calcium in the water with sodium. If you wish to use a water softener for washing, install it only on the hot water pipes, leaving your drinking water unaffected.
It is unnecessary to add a powdered or granulated water softener to a clothes washer before doing laundry or to the bathtub when you take a bath. Most detergents and bath soaps now contain softeners.
Home Treatment Devices
Denver Water neither recommends nor discourages use of home filtration devices. Our water, as it enters your home plumbing system, satisfies all safety standards. There are some problems associated with deteriorating plumbing, however, that can be alleviated with a home treatment device. If you are considering such a device, have your water tested by a state-certified commercial laboratory to identify any contaminants and then carefully research home treatment devices that are designed to remove those contaminants. If you decide to make a purchase, select one that is certified by an independent third party, such as the Water Quality Association or NSF International. And remember: To function effectively, home filtration devices require clean filters and routine maintenance.
Bottled Water
Although some individuals may prefer the taste of commercial bottled water, the source for most bottlers (90% to 95%) is municipal tap water. From a health standpoint, there is no reason to drink bottled water instead of Denver’s water, unless a customer has a special health condition, unusual sensitivity, allergy or home plumbing problem. For a fraction of the cost of bottled water, Denver Water delivers high quality water to your home.
Persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, those with HIV-AIDS or other immune system disorders, and some elderly and infants, can be particularly at risk of infections. These people should seek advice about drinking water from their health-care providers.
Get the Lead (and Copper) Out!
Lead isn’t detected in either raw water supplies or treated water leaving our plants.
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Lead’s documented health effects, in adults, include high blood pressure, hearing problems, and kidney and nervous system disorders. In infants and children, lead can interfere with formation of red blood cells, cause low birth weight, delay physical and mental development, and is a cancer risk. At high levels, copper can cause gastrointestinal difficulties.
Your residence or business might have a higher susceptibility to lead or copper if:
- The water system has lead pipes, service or fixtures containing lead;
- The structure was built between 1982 and 1987 using copper pipes joined with lead-based solder, according to the U.S. Environmental Protection Agency. The inside of pipes in older structures in our system should have sufficient mineral deposits of substances other than lead to prevent water from being in contact with the pipe. Leaded solder was banned in 1988.
If you are unsure about whether your pipes contain lead, it is best to flush the tap of any water that has been standing in the pipes. Run the tap until there is a distinct temperature change from warm to cold. This signifies that water is being pulled from the water main and has not been sitting in your plumbing. Save the flushed water in a container to water your plants.
If you want to find out if you have lead in your home's drinking water, you can:
- Have your water tested by a state-certified commercial laboratory;
- Contact the Water Quality Lab at Denver Water for more information.
Cryptosporidium and Giardia
Denver Water has tested for Cryptosporidium and Giardia in both raw and treated water since the 1980s and has never detected a viable indication of either in drinking water.
Crypto and Giardia are microscopic organisms that,
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Most people readily recover from the symptoms, which can be more serious in people with compromised immune systems. The organisms are in many of Colorado’s rivers and streams and come from animal wastes in the watershed. Crypto and Giardia are removed by effective filtration at the plant. The disinfectants we use in treatment also kill Giardia.
Watershed Protection
Denver Water always has been sensitive to conditions in its watershed.
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The inferno that swept through the South Platte River drainage and dry weather both have served to intensify our focus on watershed protection, particularly in the forest destroyed by the blaze at Cheesman Reservoir. Denver Water allocated millions of dollars for rehabilitation and erosion control in the scorched 7,250 acres surrounding the reservoir and dam.
Immediately after the Hayman fire, Denver Water built scores of silt traps and two rock dams to catch sediment in tributaries. Acres of charred trees were mulched and grass seed spread. When work is complete, many of the incinerated trees will be gone, more than a quarter-million seedlings will be growing and new vegetation planted, and what before was a well-tended alpine forest will be upland grassland.
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A Brief History
Long before the city of Denver was established, the confluence of the South Platte River and Cherry Creek was an oasis for miners and pioneers and the American Indians who traveled the semi-arid Great Plains.
They drank water directly from the creek and river, as would the early settlers. Inevitably, when the town started to develop, the purity of the water was questioned. Surface wells and buckets of water sufficed for a while, but they eventually proved inadequate.
In 1870, when the rapidly-growing community had a population of 4,759, the Denver City Water Co. was formed, and in 1872 with a large well, a steam pump and four miles of mains, it began to pump water into homes.
Over the next two decades, ten water companies fought, collapsed or merged until 1894, when the Denver Union Water Co. – predecessor of Denver Water – emerged victorious and established a stable system. Its major accomplishment was construction of Cheesman Dam on the South Platte River. When completed in 1905, Cheesman was hailed as the solution to Denver’s water storage problems.
In 1918, Denver citizens voted to purchase the private company’s water system for $14 million, creating a municipal water department with a board of commissioners independent of city hall. From that time forward, Denver Water began planning and developing a system to meet the needs of people of Denver and the surrounding areas. Today, Denver Water serves everyone in the City and County of Denver and about 25 percent of those who live in the suburbs.
Our Commitment to YouFor the better part of a century, nearly one fourth of all Coloradans have looked to us for a safe, dependable water supply. Our commitment to meeting your water needs by consistently providing high-quality water and excellent service remains strong. Ongoing development and long-range planning together with quality control, storage and distribution initiatives ensure that you and future generations will have fresh, clean water when and where it’s needed. |
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Water Quality Laboratory 303-628-5996 |
Community Affairs 303-628-6058 |
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