Important Information about Copper in Your Drinking Water

By Michele | July 30, 2026

DRINKING WATER NOTICE.

The City of Onamia has found elevated levels of copper in drinking water in some homes/buildings. Please read this information closely to see what you can do to reduce copper in your drinking water.

Elevated Levels of Copper in Your Drinking Water .

Our water system regularly samples for copper in our drinking water to make sure it meets Safe Drinking Water Act standards. More than 10 percent of the homes sampled for copper were above the Safe Drinking Water Act action level for copper. The action level for copper is 1,300 micrograms per liter (the same as 1,300 parts per billion, or ppb).

What Are We Doing about the Issue?

We are looking at ways to change our drinking water treatment. We are also adopting a copper education program for all of our water customers.

What Are the Health Effects of Copper?

Copper is an essential nutrient, but some people who drink water containing copper in excess of the action level over a relatively short amount of time could experience gastrointestinal distress. Some people who drink water containing copper in excess of the action level over many years could suffer liver or kidney damage. People with Wilson’s disease should consult their personal doctor.

Sources of Copper

Copper is a reddish metal that occurs naturally in rock, soil, water, sediment, and air. It is used to make many products, including parts for plumbing systems.

Copper can get into your drinking water as the water passes through your household plumbing system. Over time, plumbing parts usually build up a natural coating that keeps the water from absorbing copper from the plumbing.

Water may have more copper if:

• Your plumbing is less than three years old. It likely has not had time to build up a protective coating.

• It has been sitting in your home’s pipes. The water has had more time to absorb copper from the plumbing.

• You use warm or hot water. Warmer water absorbs more copper from plumbing systems.

• You have a home water softener. There may be less protective coating in homes with softened water.

Reducing Exposure to Copper in Water

1. Let the water run before using it for drinking or cooking. If you have a lead service line, letthe water run for 3-5 minutes. If you do not have a lead service line, let the water run for 30-60 seconds.

• Ways to let the water run before using it for drinking or cooking:

o Do household tasks like showering or running the dishwasher first

o Collect tap water for cleaning or watering plants,

• Make sure you let the water run from individual faucets for a short time before using them for drinking or cooking.

• Consider keeping a container of drinking water in the refrigerator to reduce how often you need to let the water run.

2. Use cold water for drinking, making food, and making baby formula. Hot water releases more copper from pipes than cold water.

3. Test your water. In most cases, letting the water run and using cold water for drinking andcooking should keep copper levels low in your drinking water. If you are still concerned about copper, arrange with a laboratory to test your tap water.

• Testing your water is important if an infant or someone with Wilson’s disease drinks your tap water.

• Search for Accredited

Laboratories (https://eldo.web.health.state.mn.us/public/accreditedlabs/labsearch.seam) to purchase a sample container and get instructions on how to submit a sample.

4. If tests show you have levels of copper over 1,300 ppb in your tap water after you let the water run 30-60 seconds, you may want to consider treating your water.

• If you use a home water softener, ensure that your softener settings are correct. Somehome treatments can increase copper levels in water.

• You can learn more about water treatment options at Home Water

Treatment (https://www.heaIth.state.mn.us/communities/environment/water/factshee t/hometreatment.html

For More Information

If you have questions about copper in drinking water, please call us at:

Gene (320-630-6450)Josh (320-630-6217)

Visit our website at Onamiamn.com

Visit the Minnesota Department of Health’s Copper in Drinking

Water (https://www.health.state.mn.us/ communities/environment/water/contaminants/copper.htm I). Date Distributed: [Aug 4, 2026);

This notice is being sent to you by:

City of Onamia

PWSID 1480003

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