Fluoride Notice

Lancaster’s water system recently violated the PA drinking water standard for Fluoride. This incident was not an emergency, but as our customers, you have a right to know what happened and what we did to correct this situation.


Lancaster staff routinely and regularly monitor and test for drinking water contaminants including Fluoride. Fluoride levels were not tested December 24 to December 27, 2022. Testing results on December 28, 2022, show that our system exceeded the PA standard, or maximum contaminant level (MCL), for fluoride. The level was 2.31 mg/L. This average may not exceed the MCL of 2.0 mg/L. Moving forward the City will be implementing multiple daily Fluoride tests and establishing additional dosage controls. Since this time all testing has been in compliance.




This is not an emergency. If it had been, you would have been notified immediately. This is an alert about your drinking water and a potential cosmetic dental problem that might affect children under nine years of age. At low levels, fluoride can help prevent cavities, but children drinking water containing more than 2 milligrams per liter (mg/L) of fluoride may develop cosmetic discoloration of their permanent teeth (dental fluorosis) over a prolonged exposure period.


Dental fluorosis is caused by taking in too much fluoride over a prolonged period when the teeth are forming under the gums. Only children aged 8 years and younger are at risk because this is when permanent teeth are developing; children older than 8 years, adolescents, and adults cannot develop dental fluorosis. This problem occurs only in developing teeth, before they erupt from the gums. Dental fluorosis, in its moderate or severe forms, may result in a brown staining and or pitting of the permanent teeth. Drinking water containing more than 4 mg/L of fluoride (the U.S. Environmental Protection Agency’s drinking water standard) can increase your risk of developing bone disease. Please note that the recorded Lancaster Fluoride level was 2.31 mg/L. Most toothpaste sold in the United States contains fluoride in the form of sodium fluoride or monofluorophosphate, most commonly at a level of 1,000 to 1,100 mg/L (about 1.3 mg in a quarter teaspoon, a typical amount of toothpaste used for one brushing). The amount of fluoride ingested from toothpaste depends on the amount used, the person’s swallowing control, and how often the person uses toothpaste. Please see below for the National Institute of Health’s fact sheet on Fluoride sources.


You may want to contact your dentist about proper use by young children of fluoride-containing products and any potential impact this short-term exposure may have on your child’s developing teeth. Older children and adults may safely drink the water.




Fluoride levels were not monitored between December 24 to December 27, 2022. Once testing resumed on December 28, 2022, fluoride levels were determined to be at 2.31 mg/L. Once the issue was discovered, additional procedures were enacted to ensure daily testing and lower process control set points were added on the Fluoride chemical feed system to ensure this type of event does not occur in the future.


Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses). You can do this by posting this notice in a public place or distributing copies by hand or mail.


Water Quality Laboratory



(717) 291-4818