Water treatment glossary

Activated carbon

Porous carbon (ours is made from coconut shell) that traps chlorine, odours and many organic chemicals.

Aesthetic objective (AO)

Ontario's limit for things that affect taste, smell, colour or staining, not health. Examples: iron 0.3 mg/L, TDS 500 mg/L.

Backwash

Reversing water flow through a filter to flush out what it has trapped.

Birm

A filter media that speeds up the reaction between oxygen and dissolved iron and manganese so they can be filtered out.

Brine tank

The salt tank beside a softener. Brine from it recharges the resin.

Catalytic carbon

Carbon treated to break down chloramine and hydrogen sulphide, which ordinary carbon struggles with.

Chloramine

Chlorine combined with ammonia, used by some cities because it lasts longer in the pipes. Harder to remove than chlorine.

Chlorine (free chlorine)

The disinfectant added to city water to keep it safe all the way to your tap.

Grains per gallon (gpg)

A hardness unit used for softeners. 1 gpg = 17.1 mg/L.

Hardness

Dissolved calcium and magnesium, measured as mg/L of calcium carbonate. The cause of scale.

Hydrogen sulphide

A gas in some well water that causes a rotten-egg smell.

Ion exchange

How a softener works: resin beads swap calcium and magnesium for sodium or potassium.

KDF 55

Copper-zinc granules that reduce chlorine and some dissolved metals, and keep working in warm water.

Maximum acceptable concentration (MAC)

Ontario's health-based limit for a substance in drinking water. Lead's MAC is 0.01 mg/L.

Micron

One-thousandth of a millimetre. A 5-micron sediment filter catches particles larger than that.

Point of entry (POE)

A system that treats all water entering the house, like a softener or whole-home filter.

Point of use (POU)

A system that treats water at one tap, like an under-sink reverse osmosis system.

Regeneration

A softener's automatic cleaning cycle that recharges the resin with brine.

Resin

The small beads inside a softener that hold on to hardness minerals.

Reverse osmosis (RO)

Pushing water through a membrane that blocks most dissolved solids, metals and salts.

Sediment

Sand, silt, rust and other particles carried in water.

Sodium silicate

Added by some municipalities to well water to keep iron dissolved so it doesn't stain.

Tannins

Organic compounds from decaying plants that turn well water tea-coloured.

TDS (total dissolved solids)

Everything dissolved in water: minerals, salts and metals. Measured in mg/L or ppm.

UV disinfection

Ultraviolet light that damages the DNA of bacteria, viruses and cysts so they can't multiply.

Water-on-water (WOW)

An RO design that uses water pressure instead of air in the tank, so there's no back pressure on the membrane.

Didn't find a term? Ask us at +1 888 701 4686, or browse the water guides.