Can You Drink Toronto Tap Water? – TDS Level Explained

Yes, tap water is safe to drink in Toronto. However, it is always safe to test the TDS level in your drinking water. TDS is an acronym for Total Dissolved Solids. This term describes the total concentration of both organic and inorganic compounds found dissolved inside water. These inorganic compounds found in water include positive ions like magnesium, calcium, potassium, and sodium. Negative ions include nitrates, sulfates, chloride, and bicarbonates. In this article, you will learn more about TDS in water and what it means for your water quality and health.

How TDS Gets in Your Water

Although Toronto’s tap water is drinkable in most areas, TDS in water is not uncommon and can result from both naturally occurring events and man-made events. Water that comes from mineral springs and deep wells often has higher levels of TDS. This is because the water in springs and wells is surrounded by rocks in its source. These rocks have high mineral salt levels, which the water picks up on its way into main water supply systems.

Water expelled by reverse osmosis systems and softeners can also get back to the main supply systems. This water contains high levels of filtered TDS, as does water flushed away from water treatment plants and salt-thawed roads during winter.

Rainwater typically has low TDS levels as it comes from the sky. However, due to the absorption of carbon dioxide in the atmosphere, it is slightly acidic. In areas with low TDS water, dissolved solids such as fluoride, magnesium, and calcium may be intentionally added to the water. These can be found in supplemented bottled water and branded mineral water.

TDS Measurements, Standards, and Guidelines

There are many reasons you should measure the TDS levels in your water, including:


High levels of certain minerals in water can cause health complications. Low levels can also cause complications as the body will lack essential minerals.


High TDS levels can cause water to taste bitter, salty, and sulfuric. This depends on the type of abundant minerals in the water. Lower levels often leave the water tasteless.

Maintenance of Water Systems

The concentration of TDS determines the functionality and lifespan of water systems. Over time, high levels may cause the systems to wear out.

For Cooking

The concentration of TDS in your water affects the quality of the food you cook and can alter the taste.

For Cleaning

Water with high levels of TDS can cause mineral residues and stains on surfaces and utensils. It can also lead to the accumulation of scales and soap scum.

You can measure the amount of TDS in your water using a TDS meter. According to the WHO, the standards are:

Level in Mg/liter Condition
Less Than 300 Excellent
300-600 Good
600-900 Fair
900-1200 Poor
1200 and above Unacceptable

Various countries have their guidelines. For Canada, the guideline is set for below 500 mg per liter. Not all regions stick to this guideline, however. In Saskatchewan, the guideline is 1500mg as it is an area with naturally occurring high TDS levels.

How Do You Get Rid of High TDS in Your Water?


This is a process through which minerals are extracted from water using an electrode. The membrane present in the water deionizer is peculiar to certain types of ions and uses the “opposites attract rule.” Cations (positively charged minerals) are drawn to the negatively charged electrode, while anions (negatively charged minerals) are drawn to the positively charged electrode. The resulting water is very pure.


This process details boiling the water and then trapping the vapor released. The resulting water is pure and free of dissolved solids.

Reverse Osmosis

Most homes, schools, and restaurants in Toronto use a water filter or have an RO system. This is a process in which water is forced through a thin membrane with microscopic pores. This filters out the tiniest of particles such that only atoms tinier than 0.0001 microns can pass through. This is done with a RO water purifier.

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