This page is a quick reference for the various terms for water and water filters.

Activated Carbon- Loose, granular carbon filter.  Most effective at removing chlorine, radon, sediment, VOCs (Volatile Organic Compounds), bad tastes & orders.  Activated Carbon can also reduce the presence of heavy metals such as Copper, Cadmium, and Mercury.  Block carbon is a more effective filter than activated carbon.

Benzene- Chemical present in gasoline and also used in plastics, detergents, lubricants, dyes, medication, and pesticides.  Has been linked to leukemia and other blood cell deficiencies.

Block Carbon– Solid, powdered carbon.  Filters more contaminants that activated, granular carbon.  Filtering time is longer than activated carbon.  Block carbon can also reduce the presence of Fluoride, Arsenic, Lead, & Chromium 6.

Carbon Filter- Water filter that removes various chemicals & metals from water source.  They come in Activated (Granular) form & Solid (Block) Form.  These filters are generally made of bituminous wood or coconut shells.  See Activated Carbon or Block Carbon for separate definitions.

Chloramines– A combination of chlorine & ammonia, this disinfectant is gaining popularity because it remains in the water supply longer which reduces the probability of bacteria growth until water exits the users tap.

Contaminant– Any chemical or substance not naturally occurring in water.  This can be residue from herbicides, pesticides, and pharmaceuticals.  Filters are recommended to remove & reduce the presence of various contaminants.

Disinfectant– Chemical added to municipal water supply to make water meet drinking (potable) quality standards.

Disinfectant By-Products (DBPs)- Chemical, organic, or inorganic substance that appears in water when a disinfectant (i.e. chlorine) reacts with naturally present material in the water.  DBPs can promote the growth of bad “Free Radicals” in your body.

Distillation– Method of water filtration where water is boiled & the captured steam is collected and used for drinking water when it cools.  Not recommended for long-term consumption for drinking water purposes.

Fluoride- A controversial chemical (Sodium Fluoride) added to water.  It is added by a majority of municipal water suppliers in the United States to officially prevent tooth decay, but the long-term health effects are unknown.

Gravity Filtration– Water filters that do not require electricity to filter water.  They depend on gravity.  Examples include carbon-based filter pitchers.  You fill the upper reservoir & the clean water passes through the filter into the lower reservoir.

Ground Water- Source of water located underground.  Also called aquifers.  They accessed by drilling a well & can be used for individual houses or municipal water supplies.  Generally less polluted than surface water due to natural filtration from the earth.

Membrane– Also known as semipermeable membranes.  They are part of the filter in Reverse Osmosis & Block Carbon Filters that blocks particles larger than a certain size (5 microns for example).  These filters are usually made of a durable plastic.

Point of Entry FilterWhole house filter.  Name refers to a water filter that begins filtering water at the source instead of where the water departs the tap (i.e. kitchen sink, drinking fountain, shower head).

Point of Use Filter- Individual filters for each tap after water travels through house.  Several examples include: a filtered pitcher, under-counter filter, shower head filter, or a filtered water bottle.

Potable– Water that meets drinking water standards.  If water is non-potable, it is not safe for drinking.

Radiological Contaminants– Various contaminants that might enter a water supply near a nuclear powerplant or heavy industry.  Contaminants include: Radon 222, Radium, Plutonium, Cesium 137, Strontium, and Beta particles.  Filters certified to remove these contaminants will typically remove other “normal” contaminants as well such as Chlorine & Mercury.

Reverse Osmosis- Considered the most thorough, but expensive, water filtration process that removes nearly every contaminant & mineral present in water.  Filters can be under-counter point of use or whole house filtration.

Surface Water- Source of water that is at ground level such as a reservoir, stream, or lake.

Suspended Solids- Particles in the water visible to the naked eye.  Examples include wood pulp or sand.  They typically do not settle to the bottom of a glass.

Total Dissolved Solids (TDS)- Any mineral, salt, metal, cation or anion that is dissolved in water and not visible to the naked eye.  These can be present from the water source originating from natural, residential, or industrial runoff.  TDS can also be present in the municipal or house pipes used to transport the water to the user.  Calcium & other minerals can qualify as TDS, so they are not all inherently dangerous like contaminants.

Ultraviolet (UV) Filtration- Final step in Reverse Osmosis.  UV lamp that removes bacteria & viruses.  Can also be used in whole house carbon filters, depending on quality of water supply.

Volatile Organic Compounds (VOCs)- Organic compounds found in water created by a chemical reaction & sometimes grouped with Disinfectant By-Products.  Can be detected by odor in water & vapors are released in greater concentration at higher water temperatures, such as a hot shower.

Well Water– Water supply for an individual house, typically in rural areas.  It is ground water accessed by drilling a well into the aquifers underneath ground level.