A Guide to Point-of-Use vs. Point-of-Entry: Where to Treat Water in Your Home

Choosing the right water treatment system begins with understanding where to tackle contaminants. The two primary approaches are Point-of-Use (POU) and Point-of-Entry (POE), each serving a distinct purpose for cleaner, safer water.

Point-of-Use (POU) Systems: Targeted Protection
POU devices treat water at a single tap or appliance, providing highly specific filtration right where you drink or use water for cooking. They are ideal for removing contaminants that pose a risk primarily through ingestion.

• Best For: Contaminants affecting taste, odor, and direct consumption.
• Common Contaminants: Lead, chlorine, volatile organic compounds (VOCs), and microbial cysts like Cryptosporidium.
• Typical Devices: Under-sink filters, countertop pitchers, and faucet-mounted filters. Reverse Osmosis (RO) systems are a powerful POU option for reducing dissolved solids like arsenic, nitrates, and sodium.

Point-of-Entry (POE) Systems: Whole-House Defense
Also called whole-house systems, POE units treat all water entering your home. They address contaminants that affect your plumbing, appliances, skin, and lungs, not just your drinking water.

• Best For: Contaminants that cause scale, corrosion, staining, or can be inhaled or absorbed through the skin during bathing.
• Common Contaminants: Sediment, iron, manganese (which stain fixtures), and hardness minerals (calcium/magnesium). They also remove chlorine, which can dry skin and damage pipes, and certain chemicals like hydrogen sulfide (“rotten egg” odor).
• Typical Devices: Whole-house sediment filters, water softeners, and large-scale carbon filtration systems.

Making the Right Choice
For comprehensive protection, many homeowners use a combined approach. A POE system, like a water softener or sediment filter, protects your home’s infrastructure and provides better water for washing. Then, a dedicated POU system, like an under-sink RO unit, delivers pristine water for drinking and cooking. Start by testing your water to identify specific contaminants, then build your defense from the main line to the tap.