Drinking Water

Have you seen our Drinking Water Publications?


child at faucet
How much do you really know about the water you drink every day?
Where does it come from? Is it safe to drink? Is a home water treatment system necessary? How can drinking water be protected?

Start with the Nebraska Extension NebGuide below.
An Introduction to Drinking Water

Then explore this site for more detailed information that will help you answer questions or solve problems you may have.


In The News: Could You Have Lead In Your Private Well Water?

By Nebraska Extension Water Quality Educator Sharon Skipton and Nebraska Extension Specialist Bruce Dvorak

You have probably heard about elevated lead levels in Flint, Michigan’s drinking water and you may be wondering if you could have lead in your private well water.

In most situations, including Flint, lead contamination takes place at some point in the water delivery system. This occurs as a result of corrosion, the reaction between the drinking water and lead that has been used to construct parts of the water delivery system. Did you know that lead in drinking water from plumbing or fixtures is most often a problem in either very old or very new homes and buildings? It’s true, but any home or building may be susceptible.

Through the early 1900's it was common in some areas of the country to use lead pipes for interior plumbing. Lead piping is most likely found in homes and buildings built before 1930. Copper piping replaced lead piping, but lead-based solder was used to join copper piping. It is likely lead-based solder was used in any home built before 1988.

Today, brass materials are used in nearly 100 percent of all home water distribution systems. Many household faucets, plumbing fittings, check valves and well pumps are manufactured with brass parts. Brass contains some lead to make casting easier and the machining process more efficient. As of January 2014, federal regulations allow no more than 0.25 percent lead content of brass plumbing components labeled “lead free.” “Lead free” brass components manufactured before that date could have as much as 8.0 percent lead content.

Some private wells may have submersible pumps containing brass or bronze capable of leaching lead. Some well screens also may contain lead or were installed with a “lead packing collar.” Potential lead contamination also exists if the well is a driven, sandpoint well and has been “shot” to clear the screen. Lead shot was sometimes poured into a well to keep out sand. In other wells, lead wool was used. While these were acceptable practices at the time, none of these practices are recommended, and sandpoint wells driven into the ground are not approved for drinking water purposes under Nebraska well construction regulations.

The characteristics of water vary greatly depending on the source of the water. Some water is naturally more corrosive and will be more likely to dissolve lead. Several factors cause water to be corrosive including low pH (pH less than 8.0), high temperature, low total dissolved solids (TDS) content and high amounts of dissolved oxygen or carbon dioxide. Generally, naturally soft water is more corrosive than hard water because it is more acidic and has low TDS. Treating naturally hard water with an ion exchange water softening unit, reverse osmosis unit, or distillation unit may change the water chemistry significantly enough to have an effect on the water’s ability to dissolve lead.

Often, hard water minerals deposit on the interior of plumbing. These deposits form a mineral scale lining, such as calcium carbonate, inside pipes and fittings, which protects against lead contamination. It may take up to five years for an effective mineral scale lining to form. Treating naturally hard water with an ion exchange water softening unit, reverse osmosis unit, or distillation unit can either prevent or dissolve the scale, eliminating its possible protective effect.

If you want to know if lead is present in your private drinking water supply, you will need to have the water tested. Although private water supplies are not subject to any regulations concerning lead contamination, you may want to test your water supply, especially if lead is suspected or if children or pregnant women consume the drinking water.

Tests to determine the presence of lead in drinking water should be done by a laboratory approved for lead testing. The Nebraska Department of Health and Human Services approves laboratories to conduct tests for drinking water supplies.

To determine if lead is present in a private drinking water supply and to determine the possible source of the contamination, water must be tested using specific sampling procedures. Carefully follow all directions provided by the laboratory and use provided containers when collecting water samples.

In general, water that comes in contact with lead in the plumbing will continue to dissolve lead over time. For this reason, the highest lead concentration in drinking water will result from water that has sat motionless in the plumbing system, in contact with lead-containing components, for an extended period of time (e.g., several hours or overnight). To evaluate the highest lead concentration, collect a sample of the water that has sat motionless in the plumbing system, in contact with suspected lead-containing components for six or more hours. This is sometimes called a “first-draw” sample.

The length of time the tap should be run prior to collecting the water sample will depend on where the suspected lead-containing components are located in relation to the tap being used. Collect the very first water drawn if suspected lead-containing components are close to the tap. Collect water drawn after the tap was run for a few seconds to a minute or two if suspected lead-containing components are present in the water delivery system farther away from the tap (e.g., in pipes, well pumps, etc.). Try to time the water collection process to obtain a sample representative of the highest contamination. If it is not known if or where lead-containing components might be located, collect the first water drawn. If there is a great concern, you can collect multiple samples from the tap that span a time frame from first water drawn to water that takes a few minutes to pass through the system.

Environmental Protection Agency regulations for public water supplies, and Nebraska regulations do not apply to private drinking water wells. However, you may consider the EPA established action level of 15 parts per billion as a guideline in assessing the risk associated with your water supply. If lead concentrations are found to be above 15 ppb, you might voluntarily consider EPA guidelines, and try to reduce the lead concentration in the water, taking into account health risks, costs, and benefits.

If water tests indicate lead is present in drinking water and testing determines the source is household plumbing, you should first try to identify and eliminate the lead source. If it is neither possible nor cost-effective to eliminate the lead source, flushing the water system before using the water for drinking or cooking may be an option.

Flushing the system involves disposing the water that has sat motionless in the plumbing system, in contact with lead-containing components, for an extended period of time. Anytime the water has not been used for several hours, the water should be run until it becomes as cold as it will get. This could take as little as thirty seconds or longer than five minutes depending on the system. Each faucet must be flushed individually before using the water for drinking or cooking. Water run from the tap during flushing can be used for non-consumption purposes such as watering plants, washing dishes or clothes, or cleaning.

In addition, you should avoid cooking with or consuming water from hot-water taps. Hot water dissolves lead more readily than cold water. Especially avoid using water from a hot water tap for making baby formula.

Several treatment methods are suitable for removing lead from drinking water, including reverse osmosis, distillation, and carbon filters specially designed to remove lead. Typically these methods are used to treat water at only one faucet. Reverse osmosis units can remove approximately 85 percent of the lead from water. Distillation can remove approximately 99 percent. Simply boiling water does not remove lead. A water softener can be used to pretreat water for either a reverse osmosis or distillation unit when water is excessively hard. Low flow rates are required when using lead selective carbon filters. Typically they have flow controllers which limit the system to 0.25 to 0.5 gallons per minute.

In summary, lead rarely occurs naturally in drinking water. It is more common for lead contamination to occur at some point in the water delivery system. To determine the presence of lead in drinking water and its possible source, a specific procedure must be used to collect samples and a certified laboratory should be used for testing. Management of a private drinking water well for lead is a decision made by the well owner and/or water user. A water test is the only way to determine the lead concentration. If drinking water exceeds the EPA lead standard of 15 ppb, steps can be taken voluntarily to reduce the risk. Options include removing the lead source, managing the water supply used for drinking and cooking by flushing water with high lead concentrations from the water system, using water treatment equipment, or using an alternative water source. Options selected must be based on the specific situation.

For more information see the Nebraska Extension NebGuide “Drinking Water: Lead.”

http://extensionpublications.unl.edu/assets/pdf/g1333.pdf

 

 




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