tel: 905-525-2181

Attention to users of the Ancaster Well

On January 1, 2018 the maximum legal limit for arsenic in drinking water wells, as established by the Ontario Ministry of Environment and Climate Change, will be 0.010mg/L.

The concentration of arsenic in the water at the Ancaster Well has always been below the existing legal limit of 0.025mg/L, consistently measuring between 0.017mg/L and 0.023mg/L over the past 5 years, but it will fail to meet the new standard.

City of Hamilton Public Health Services informed the HCA about the regulatory change and the requirement to comply with the new provincial drinking water quality standard. HCA staff have recommended that the well be closed by the end of December 2017.

What is Arsenic?

Arsenic is a naturally occurring element. Trace amounts of arsenic are found in food, water, soil and air. Breakdown and erosion of arsenic-containing minerals in soils and rock, agricultural run-off, mining operations and industrial processes are all potential sources of arsenic in surface and ground water.  Amounts of arsenic found in drinking water are generally higher in groundwater than surface water sources.

What are the Ontario Drinking Water Standards?

The Ontario Drinking Water Standards are provincial regulations that outline the maximum concentrations of bacteria and chemicals that are allowed in public drinking water. They must be met by all public drinking water systems and are used as recommended limits for private drinking water wells.

The provincial arsenic standard or limit is being lowered to align with the more protective federal limit which is based on the best worldwide health information available to Health Canada. The current Health Canada Canadian Drinking Water Quality Guideline limit for arsenic is already set at 0.010mg/L. The World Health Organization (WHO) limit is also set at 0.010 mg/L.

What are the health effects of high arsenic levels?
Arsenic is considered to be a Human Carcinogen, meaning it is a known substance that can lead to cancer. Long-term consumption of drinking-water and food prepared with high levels of arsenic can cause cancer and skin lesions. It has also been associated with developmental effects, cardiovascular disease, neurotoxicity and diabetes. Short-term exposure to very high levels of arsenic can lead to abdominal and muscular pain, diarrhea and vomiting, skin rash and numbness.

For more information on the risks of arsenic in drinking water please see:

I want to know more about the Ontario Drinking Water Standards, who do I contact?

You can contact City of Hamilton Public Health’s Safe Water Infoline at 905-546-2189 from Monday to Friday 8:30 am to 4:30 pm.  More information is also available on the City of Hamilton website

Are there any other areas where the Ancaster Wells do not meet drinking water standards?

The sodium level in the Ancaster Well water is above the recommended level of 20 mg/L.  Signs warning people with hypertension (high blood pressure) or congestive heart failure or following a sodium restricted diet to consult with their doctor before drinking the water have been posted on site for several years, along with regular water test results. Because sodium is not considered to be a carcinogen and the issue of high sodium pertains only to select portion of the population, the site has been permitted to remain open by posting with appropriate cautionary signage.

Can the water be treated to make it safe?

Various methods of arsenic removal and treatment methods for drinking water have been reviewed by the HCA. The resulting estimates for treating the water are not economically feasible.

Are there similar wells like this that I can go to instead?
The Hamilton Conservation Authority is not aware of alternative well locations.

What is the Hamilton Conservation Authority (HCA)’s role and position on this?

The Ancaster Well’s site has been under the HCA’s ownership and jurisdiction since the late 1990s and as a legacy well it has remained as an open public water source. This is a very unique situation for the HCA and is the only one of its kind throughout the HCA’s owned and managed properties. Providing publicly accessible drinking water is not within the mandate of the HCA. Also, the HCA is obligated to abide by government rules and regulations as they apply.

What are the next steps?

The Hamilton Conservation Authorities’ Board of Directors, will be considering the official closure of the site during the November 2, 2017 board meeting.

Information regarding this meeting and previous HCA board meeting minutes can be found here:

Comments are closed.