Water Treatment Glossary: Simple Definitions for Homeowners

Water treatment can feel technical, but it doesn’t have to be. This glossary explains the most common terms you’ll see when researching water systems in Ontario — in simple, homeowner‑friendly language.

Water Quality Terms

Hardness

Hardness is dissolved calcium and magnesium in your water which comes from groundwater as it travels through the rock formations underground. Hard water causes scale buildup, soap scum, and wreaks havoc on appliances.

Iron

Iron can be present, primarily in rural properties that have a well. This mineral causes orange staining, a metallic taste/smell, and change the water to a yellow-brown colour.

Tannins

Tannins are naturally occurring organic compounds found in well water that cause yellow or tea-coloured water.

Chlorine

Municipal water treatment facilities add this disinfectant into the water to protect people from bacteria. Once chlorine has sanitized the water, the leftover chemical makes drinking water taste awful. Chlorine also damages rubber seals in appliances and can cause itchy dry skin.

Chloramine

Cities like Kitchener, Waterloo, Cambridge, and Guelph have started using chloramine to treat the water. This is a blend of chlorine and ammonia which enables the chlorine to last longer in the distribution process. It’s important to know the difference because this chemical blend is much harder to remove than chlorine on its own. Chloramine also still has all the same effects as chlorine.

Sediment

Sediment is found in both city and well water. Sediment is any natural erosion such as sand, silt, or soil that cause cloudiness in the water. Sediment can also get inside the gearing of your appliances and clog up your pipes if they are not protected by filters.

Water Treatment Systems

Water Softener

Water softeners remove hardness in your home by swapping out the calcium and magnesium ions for sodium. Soft water can only be achieved by using salt for that ion exchange. Soft water means no scale buildup, softer skin and hair, cleaner and brighter laundry, and longer lasting appliances.

Reverse Osmosis (RO)

Reverse osmosis water goes through a semi-permeable membrane and traps contaminants in the water so that all that is left is completely purified water. Depending on the strength of the membrane, 99% of contaminants are removed and the total dissolved solids (TDS) are greatly reduced. A reverse osmosis system is a convenient way to get purified water in your home.

Iron Filter

Iron filters are large filters that use air injection to separate the iron from well water. Then the leftover iron is trapped inside the tank and cleans it out in a backwashing cycle. This ensures that there is no discolouration or odor in the household. Iron treatment is not necessary for the majority of households in the city since iron treatment is taken care of by most municipalities.

UV System

An ultraviolet (UV) system is a chemical-free way to disinfect bacteria from rural well water. It uses ultraviolet light to render bacteria inert, basically causing the bacteria to become inactive. It can clean water of not just bacteria, but also viruses. UV treatment is not necessary for households on city water since all bacteria is killed off by the chlorine or chloramine provided by the city.

Technical Terms

Regeneration

Regeneration refers to the cleaning cycle in a water softener where the system flushes out the hardness minerals that it has collected over time. Regeneration might be set for early hours in the morning while people are asleep, or with a dual tank system it will regenerate on demand. It is not recommended to force a regeneration; the water softener will automatically do that on its own.

Flow Rate

The amount of water that can move through a system at once. It’s important for a water specialist to know the flow rate in a house so that they can properly size the equipment.

Micron Rating

A measurement of how fine a filter is — lower numbers mean finer filtration. Depending on the equipment that the filter is in front of, different microns could be used. For instance, a 5 micron filter should be in front of a UV light, but only a 20 micron filter is needed in front of a water softener.

Brine Tank or Salt Tank

The tank where salt is put in a water softener. This should always be halfway full of salt. We recommend using a hard pellet salt, so it doesn’t cause issues with the water softener. There will be a few inches of water on the bottom of the salt tank, but you do not need to add any water, the water softener will do that on its own.

Media Bed

There are different types of media for different water treatment systems, but all of them are referred to as media beds. This would be resin in a water softener or carbon in a dechlorinator.