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Silica, also known as silicon dioxide (SiO₂), is a natural compound found in various forms such as sand, quartz, and granite. It can sometimes be present in well water, giving it a light yellow to brown color. While silica itself is not a health risk, it can affect the appearance of your water, making it look discolored. This discoloration is often mistaken for other contaminants, but silica is generally harmless.
What are the Effects of silica in Well Water?
Scaling and deposits on household appliances and plumbing.
Light Yellow to Brown Discoloration
When should I test for silica in my well water?
There are no guidelines set for silica in water. It is found naturally in many foods and is not harmful to human health. Silica concentrations above 25 mg/L in well water may cause scaling, deposits, or discoloration though.
To ensure you are protecting your family’s health, we have developed a set of recommendations for testing that are provided in our article, "What do I need to know about sampling my well water?.
What treatment should I use if there is silica in my well water?
Once you test and have decided to treat your water to remove silica the Minnesota Department of Health has developed a Home Water Treatment Guide that covers treatment for many common constituent in well water. While this guide does not cover silica, it does cover treatment options such as reverse osmosis or ion exchange which may reduce the amount of silica in your well water.
The most important advice we can provide you is if you are going to add treatment to your home water system, be sure the treatment device has been certified to remove silica by an independent third-party certification organization.
Where can I get local help and information about silica in my well water?
Contact your local health department – They can help you interpret your sample results and may have information on the best treatment options for your situation. If they personally aren’t able to answer your questions, they will know who to contact who will be able to help you, likely at your state health department.
Contact a water treatment professional - we would recommend contacting a water treatment professional who has been certified through the Water Quality Association’s Professional Certification Program.
State or Federal Geologic or Water Resource Agency – they may have completed field studies of your area or collected samples from water wells to map and understand the water quality in your state. In addition, they may house water well logs, including yours, or be able to provide additional information about the aquifer your well is getting water from.
Consult your well driller or drilling contractor – the contractor that drilled your well, and other local contractors, may be aware of the water quality issues nearby including high iron, and might have worked with other well owners in your area to solve this issue .
Research online – you should be inquisitive; it will help you significantly because there may be great information available online. Use search terms like “my state (CA, ME, IL, etc.) water well logs”, “my state groundwater quality”, or “my state well water quality”.
Contact us directly – if these other local sources don’t work out for you, we may be able to help. We may be able to provide direct assistance, and/or direct you to a technical assistance provider in your area who can help answer your questions (free service funded by USEPA).
Additional Resources
Home Water Treatment-Minnesota Department of Health
Want to learn more about your private well and how to care for it?
Sign up for the free 10-week email course from PrivateWellClass.org. The class is a project of RCAP and the University of Illinois, with funding from USEPA.
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