Water Filtration & Treatment

This category covers point-of-entry and point-of-use equipment for water filtration and treatment in homes and light commercial buildings. A water filtration system removes sediment, chlorine, chloramine, and other contaminants as water passes through cartridges or media tanks. A water softening system reduces calcium and magnesium hardness through ion exchange, which limits scale in pipes, fixtures, and water heaters.

Products are grouped into filter systems and softeners, with replacement cartridges and parts available for ongoing service. Whole-house units connect to the main service line and treat every fixture. Under-sink and reverse osmosis units are installed at a single faucet for drinking and cooking water. Whole-house and softener units typically use 3/4 in. or 1 in. NPT connections and a bypass valve for service. Select equipment based on water source, test results, flow demand, and available space at the point of installation.

Water Filtration and Treatment Products

Whole House Filtration Systems

Built for residential water filtration at the point of entry, these units mount on the main line after the meter or pressure tank and treat water for every tap, shower, and appliance. Cartridge formats use sediment and carbon block stages. Tank formats channel water through catalytic carbon, which reduces both chlorine and chloramine, or KDF media.

Under-Sink and Reverse Osmosis Systems

Point-of-use systems install under a kitchen or bar sink and feed a dedicated faucet. Reverse osmosis units force water through a semi-permeable membrane after sediment and carbon pre-filters, using either a storage tank or a tankless design. These water purification systems reduce dissolved solids, lead, and fluoride at the drinking-water tap.

Well Water and Iron Filtration

Private wells often carry iron, manganese, and hydrogen sulfide, which stain fixtures and cause odor. Air-injection filters oxidize these into particles the media bed traps, then backwash them to drain. A UV stage, installed after filtration, is added when a water treatment system needs to control bacteria and viruses.

Salt-Based Water Softeners

A salt-based water softening system exchanges calcium and magnesium ions for sodium or potassium in a resin tank. A metered control valve measures water use and starts regeneration when resin capacity runs low. Capacity is rated in grains, typically 24,000 to 64,000 grains for residential units.

Salt-Free Conditioners and Scale Control

Salt-free conditioners use template-assisted crystallization media to change hardness minerals into crystals that do not bond to surfaces. This type of water treatment equipment needs no brine, drain line, or electricity. It controls scale but does not remove hardness, so water tests will still show the same grains per gallon.

Replacement Cartridges and Media

Cartridges fit standard 2-1/2 in. and 4-1/2 in. diameter housings in 10 in. and 20 in. lengths. Sediment cartridges typically last 3 to 6 months, and carbon blocks 6 to 12 months. Housings, wrenches, and O-rings for cartridge-based water filtration equipment are listed under Water Filter Accessories.

How It Works and Where to Use It

Point of Entry vs. Point of Use

Point-of-entry (POE) equipment treats all water entering the building. Point-of-use (POU) equipment treats water at one outlet. Many installs pair a whole house filter with an under-sink RO unit for drinking water.

Installation Sequence

On a combined water treatment system, sediment and carbon stages go first to protect softener resin from grit and chlorine. The softener follows. UV installs after filtration, and RO installs last at the tap, where softened feed water extends membrane life.

City Water vs. Well Water

Municipal water usually needs carbon for chlorine or chloramine, plus a softener where hardness exceeds about 7 grains per gallon. Well water often needs sediment, iron, and sulfur treatment, plus UV if testing shows bacteria. Both sources benefit from residential water filtration sized to the home's peak demand.

Key Specifications and Planning Steps

Flow Rate and Connection Size

Size equipment to peak flow, not average use. Most homes with two to three bathrooms need 8 to 12 GPM. Match inlet and outlet size to the service line, usually 3/4 in. or 1 in. NPT, to avoid a pressure drop.

Capacity and Water Testing

Test hardness, iron, TDS, and pH before selecting water filtration equipment. For softeners, multiply hardness in grains per gallon by household daily gallons to find grains removed per day, then choose a capacity that regenerates every 7 to 10 days.

Certifications

Check listings against NSF/ANSI 42 for chlorine, taste, and odor; 53 for lead, cysts, VOCs, and PFOA/PFOS; 58 for reverse osmosis; 44 for softeners; and 61 for components. Wetted parts must meet federal lead-free requirements.

Installation Requirements

Plan for a bypass valve, a floor drain or standpipe with an air gap for backwash, and a 120V outlet for control valves. Keep equipment level, frost-free, and within its rated pressure range.

Choosing the Right Water Filtration System

Start with a water test. Results determine the equipment. Chlorine taste or odor points to carbon filtration. Scale on fixtures and hardness above about 7 grains per gallon point to a water softening system. Where a drain or brine tank is not practical, a salt-free conditioner controls scale without removing hardness. Staining or sulfur odor on a well points to iron filtration. Where drinking water quality is the main concern, add RO at the kitchen sink. Confirm connection size, drain access, and space before ordering any water filtration system.

Frequently Asked Questions

Do I need a water filtration system or a water softening system?

It depends on the water test. A filtration system removes contaminants such as sediment, chlorine, chloramine, and lead. A softening system removes the calcium and magnesium that cause scale. If the water tastes of chlorine and also tests above about 7 grains per gallon of hardness, the home needs both.
 

What size water softener do I need?

Multiply water hardness in grains per gallon by daily household water use. Four people using about 75 gallons each at 10 gpg produce roughly 3,000 grains of hardness per day, so a 32,000-grain softener runs about 10 days between regenerations. For well water, add about 4 gpg to the hardness figure for each ppm of dissolved iron.
 

Why did water pressure drop after installing a whole-house filter?

The usual causes are an undersized system for peak flow, connections smaller than the service line, or a clogged cartridge. Choose equipment rated at or above the home's peak GPM, match 3/4 in. or 1 in. connections to the main line, and replace sediment cartridges on schedule.
 

Which NSF/ANSI certifications matter for lead and PFAS reduction?

Look for NSF/ANSI 53 for lead and PFOA/PFOS reduction in filters and NSF/ANSI 58 for reverse osmosis systems. NSF/ANSI 42 covers chlorine, taste, and odor only. Check the certification listing for the specific contaminant claim, not just the standard number.
 

Should the filter go before or after the water softener?

Install sediment and carbon filtration before the softener. Sediment protects the control valve and resin bed, and carbon removes chlorine that degrades resin over time. Reverse osmosis goes after the softener at the point of use, since softened feed water reduces membrane scaling.
 

How often should cartridges in a residential water filtration system be changed?

Sediment cartridges typically need replacement every 3 to 6 months and carbon block cartridges every 6 to 12 months. RO membranes last about 2 to 3 years. High sediment loads, well water, or heavy use, shortens these intervals. A pressure drop across the housing is the clearest sign a cartridge is loaded.