Are there more pollutants in drinking water today than there were 25 years ago?
Not for Eden Prairie’s water. Eden Prairie’s deep aquifer is a very safe source of drinking water, and the battery of tests performed on our water at the source, during treatment and at the tap, ensure the water is totally safe for consumption.
Do I need to take special precautions with drinking water?
Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium are available from the Safe Drinking Water Hotline at 800-426-4791.
Do we have less water than we did 100 years ago?
We have the same amount of water on Earth today as we did 3-billion years ago. The difference is that today many more demands are placed on the same amount of water. These increased demands have created a different kind of water – water that is regulated, treated and sold. Because the demands on water continue to grow while supplies remain stable we have to count on everyone to help conserve and protect our water resources.
How do I know if there is lead in my drinking water?
There are no homes in Eden Prairie that have been identified through testing as having lead or copper in the drinking water. The majority of homes in Eden Prairie were constructed after plumbing code safeguards against lead and copper leaching were implemented.
Lead gets into your water after it enters your property. The most likely sources of lead in water are lead solder or brass fixtures in your home’s plumbing.
Is “new” water better than treated water?
Very little water on Earth is "new." Most of our water has been touched by some type of human or animal activity. Even in pristine wilderness areas, studies have found bacteria contaminating water. Therefore, it's always best to drink water that you know has been treated.
Is it true that once you use water, it's gone?
Not exactly. It is true that all the water that ever was and ever will be is in the Earth’s environment today. It simply changes physical form or is relocated to another place.
The overwhelming majority of the water we withdraw from our drinking water wells winds up on Eden Prairie’s lawns. This irrigation water either soaks into the ground, or evaporates into the sky. The water vapor in the atmosphere eventually comes back to Earth as rain, snow, sleet, hail, etc., but it always falls back to Earth far from where it evaporated into the air.
The water that soaks into the ground will either be absorbed by plants (the grass on your lawn) and ultimately passed into the atmosphere, remain perched within the soil, or will migrate through the soil and into a stream.
Almost all of Eden Prairie’s water that is not used for irrigation finds its way into the sanitary sewer system (between 5- and 8-million gallons of water each day). This water is treated and released into the Minnesota River, ultimately combining with the Mississippi River a few miles away. So in a sense, Eden Prairie’s valuable ground water pumped from wells far beneath the surface of the ground is contributing to the flow of the mighty Mississippi.
Is the fluoride and chlorine in my drinking water safe?
Yes. When added to water (or if naturally present in the correct amounts) fluoride greatly improves dental health. Long-term, qualitative studies have shown that fluoride in drinking water is actually reversing tooth decay among adults. We’ve known for years that fluoride enhances the formation of enamel on the teeth of growing children, but now that many decades of fluoride use can be documented, we are seeing significant long-term benefits to older people as well.
By law, all public water systems must ensure the drinking water is not only safe at the point of origin, but also at the point of use. Eden Prairie’s well water contains no bacteria, and the treatment process prevents the introduction of germs. To ensure your drinking water remains safe throughout many miles of water main, a very small amount of chlorine is added before the water leaves treatment. Because Eden Prairie is a very young community, and our water mains are so new, there is almost no consumption of chlorine within our community water distribution network. We also work very hard at keeping the water mains clear of debris and rust and biological film that inevitably accumulates in large pipes over the decades. Having newer, clean pipes results in less chlorine being needed to keep the system safe. Eden Prairie’s chlorine residual is remarkably low for a community of this size.
Minnesota well water naturally contains a lot of dissolved iron. Eden Prairie’s water softening treatment process removes nearly all of the naturally occurring iron within the water. However there is just enough iron remaining after treatment, that some of the remaining iron can precipitate out of the water when it is exposed to chlorine for a longer period of time.
During the spring, summer and autumn months, our customers use enough water for irrigation and other purposes to keep the water flowing quickly through the water mains. The water never has an opportunity to age. During the winter months, however, water use is much, much lower, allowing the water to flow very slowly through the large water mains. This longer exposure time contributes to the precipitation of iron in the water mains. It is a very small amount of iron, but enough to settle out in the bottom of some of the water mains.
Eden Prairie Utilities Division personnel flush the entire City water distribution system every spring to remove this sediment. During the flushing period, there are a few places in town where this “rusty” water can accumulate, and if you happen to turn on your faucet in that particular neighborhood where the crews are flushing, it is possible that you might draw some of this reddish water into your home before it has a chance to be flushed out into the street. If this happens, turn on your cold water faucets throughout your house, and let the water run for about five minutes to clear the lines.
What chemicals are used in the treatment of Eden Prairie’s water?
Water withdrawn from the City’s 15 water wells is very pristine. It could be safely consumed without treatment of any kind.
Eden Prairie softens the water using a process that bonds the naturally occurring calcium and magnesium in the water to a form of calcium introduced into the water as lime. The lime bonds with the calcium and magnesium to form particles large enough to settle or precipitate out of the water. Calcium is the predominant cause of hardness in water, so this precipitation process results in much softer water.
Minnesota well water also naturally contains a significant amount of dissolved iron. The iron is harmless, but gives the water a bad taste. The lime softening process also removes the dissolved iron from our water, making it very palatable.
Another additive, ferric chloride, is dissolved into the water after softening to enhance the precipitation process by forming “clinging” particles or “floc” that adhere to one another and to particulate matter in the water. Any particles remaining from the softening process are captured in this form of treatment by the clingy floc, and the floc begins sticking to itself until the particles become large enough and heavy enough to settle to the bottom of the treatment basin. The “stickiness” is caused by an electro-chemical bond between the floc and the particulates in the water, similar to when you rub a balloon on your head and stick it to the wall. The particles and the floc in the water move toward one another just as the balloon moves toward the wall.
As the water leaves this process, chlorine is introduced in minute amounts to ensure the water remains free of bacteria in the distribution system.
A chemical called polyphosphate is added to the water to ensure the liquid does not corrode the plumbing in your home. This protects you from lead or copper contamination that could otherwise leach from the pipes within your home.
Carbon dioxide may be used at times in small quantities to keep the water from becoming too acidic – another anti-corrosion measure. Carbon dioxide is a naturally occurring substance already found in ground water.
Fluoride is an important addition to Eden Prairie’s drinking water. All public water systems are required to ensure that public drinking water contains a very small quantity of fluoride to enhance the prevention of tooth decay.
Eden Prairie tap water averages 5 grains per gallon, or 90 milligrams per liter of total hardness.
Hardness in water is an expression of the amount of dissolved minerals. The two most common minerals found dissolved in drinking water contributing to water hardness are calcium carbonate and magnesium carbonate.
The average hardness of Eden Prairie’s combined well water prior to treatment is around 360 milligrams per liter, or about 21 grains per gallon.
Residents of Eden Prairie do not need a water softener. Eden Prairie is one of the very few communities in the metropolitan area that softens its public water supply. The City’s water treatment softening process removes the calcium hardness from the water, as well as iron and manganese common in Minnesota water supplies, achieving the results you would expect from a home softener.
When my water comes out of the tap, it looks cloudy, but then clears up. Should I be concerned?
The cloudy water is caused by tiny air bubbles in the water similar to the bubbles in carbonated soft drinks. After a while, the bubbles rise to the top and escape into the air. This type of cloudiness occurs most often in the winter when the drinking water is cold. Warm water is able to contain more oxygen than cold water. When the relatively warm well water leaves the treatment system, it travels through pipes in the frozen ground to your home. The water is cooled and is not able to retain as much oxygen, but because the water is trapped in a pipe the oxygen cannot escape. When you open your tap, the water is no longer trapped inside the pipes, and the oxygen immediately begins to escape (or bubble) to the surface.
Where can I find information about Eden Prairie drinking water quality?
Information about Eden Prairie's drinking water and other water-related information is available in the Groundwater and Drinking Water section of the website.