Legend Lake wells face hard water, arsenic risks, experts say

Scale on faucets and staining in sinks around Legend Lake can point to hard well water, and Menominee County material also flags arsenic in some local groundwater. The county points to increased levels of iron and magnesium in parts of the area’s water table, and those cations can make well water hard.

What Legend Lake water problems can look like

Cations are positively charged elements that occur naturally in groundwater. Around Legend Lake, elevated iron and magnesium can create hard water, the kind that leaves spots on dishes, builds scale in pipes and fixtures, and makes appliances work less efficiently.

Hard water is not the same thing as a contaminant emergency. Iron staining, mineral buildup and cloudy water can be frustrating for families, cabin owners and short-term-rental hosts who may assume clear water is automatically safe. Menominee County also notes arsenic in some local groundwater, and arsenic is a different problem altogether.

Test first, then decide what problem you actually have

Testing is the only way to know what is in private well water. A well can taste fine, look clear and still carry contaminants that move through soil and bedrock without being filtered out.

The DNR recommends testing private wells annually. The Wisconsin Department of Health Services says private well owners should test for arsenic at least once every five years. If arsenic showed up before, or if a home is in Outagamie, Winnebago or Brown counties, DHS says to test once a year for arsenic. And if arsenic is detected, DHS says to collect a second sample to verify the result.

For Wisconsin well owners, the key questions are simple:

• Is this just hardness, with mineral buildup and spots?
• Is there iron or another nuisance mineral problem?
• Is there a contaminant concern such as arsenic, bacteria or nitrate?

Why the issue is bigger than one lake

Nearly four in 10 homes in Wisconsin rely on private wells for their water supply, and well owners are responsible for testing their own water. The DNR says most private wells provide safe drinking water, but some become contaminated with bacteria and other contaminants that are not filtered out as water soaks into the ground.

Clear water can still carry arsenic, and well water that causes scale or spots may also need a closer look for other issues. In a lake-country setting where homes may sit on private systems rather than municipal treatment, the cost of guessing wrong falls directly on the household.

Match the treatment to the problem

Menominee County’s guidance draws an important line between two common fixes. Water softeners can help with hardness, while reverse osmosis systems can reduce substances such as arsenic.

A softener and a reverse osmosis unit do not do the same job. A softener is aimed at the hardness problem tied to minerals such as iron and magnesium. Reverse osmosis is a different treatment used for drinking water, and it is the kind of system the county points to when the concern is arsenic.

A practical setup for a Legend Lake home may look like this: 1. Test the water before buying any equipment. 2. Identify whether the main issue is hardness, iron staining or a contaminant such as arsenic. 3. Use a softener for hardness problems. 4. Use reverse osmosis when arsenic reduction is the goal. 5. Retest after treatment is installed to make sure the system is doing what it should.

Why arsenic deserves a closer look

Arsenic is a naturally occurring element found in soil and bedrock throughout Wisconsin. Under certain conditions, it can be released into groundwater and enter water wells. Long-term exposure to arsenic in drinking water is known to increase risks of several cancers and other health effects.

That concern is not new in northeastern Wisconsin. A Wisconsin Water Well Association conference presentation in 2002 said naturally occurring high levels of inorganic arsenic had been found throughout the state. A 2003 Wisconsin Geological and Natural History Survey report examined geologic and geochemical controls on arsenic in groundwater in northeastern Wisconsin. A 2016 Wisconsin Watch report said arsenic continued to poison many private wells in Wisconsin despite state efforts.

A plain-language homeowner checklist

If you own a well around Legend Lake, the decision tree is straightforward:

• Test the water annually, even if it looks fine.
• Ask whether the issue is hardness, iron staining, bacteria, nitrate or arsenic.
• Use a softener for hardness.
• Use reverse osmosis for arsenic reduction in drinking water.
• If an arsenic result comes back positive, send a second sample to confirm it.
• Retest after new construction, plumbing changes or a treatment-system installation.