Home / Whole House Softeners Versus Point of Use Filters
Whole House Softeners Versus Point of Use Filters
Hard water can be dealt with in two broad ways. One treats every drop that enters the house, from the shower to the hose bib. The other treats only the water at one tap or one appliance. Both have a place, and the right choice depends on what is bothering the household, how much room is available, and what the water is meant to do.
Two different jobs
The word treatment covers very different technologies, and mixing them up leads to disappointment. A softener removes the minerals that cause scale. A filter removes particles, chlorine taste and some contaminants but usually leaves the minerals alone. A softener makes water gentler on pipes and appliances while a typical carbon filter makes it taste and smell better. Many households need one, some need both, and a few need neither.
How a whole house softener works
A salt based softener is a tank filled with small resin beads that carry a charge. As hard water flows through, the calcium and magnesium ions cling to the beads and sodium ions are released in exchange. The water leaving the tank is soft. Eventually the beads fill with minerals and must be cleaned, so the unit periodically flushes itself with a strong brine from a second tank, called the regeneration cycle, and sends the waste water to a drain. The system needs a drain line, a nearby electrical outlet, a water connection with bypass valves and a steady supply of salt.
The benefit is felt throughout the house: less scale in water heaters and pipes, cleaner fixtures, softer feeling laundry, and often less soap needed. Water heaters in particular last longer and run more efficiently when scale is prevented from coating the tank and elements.
What a point of use filter does
A point of use system sits at a single location, often under the kitchen sink. The common type is a reverse osmosis unit, which pushes water through a very fine membrane that removes dissolved minerals and many other substances, delivering a small amount of very pure water to a dedicated faucet. A tank stores the water so it is ready when the faucet is opened. Simpler cartridge filters, such as carbon blocks, attach to the cold supply line and improve taste without removing hardness.
Because it treats only the drinking and cooking supply, it protects nothing else. The dishwasher, the water heater and the bathrooms still receive hard water. It is a good answer when taste and drinking quality are the concern, and a poor answer to scale across the house.
Comparing the two
- Coverage. A whole house unit protects plumbing, heaters, appliances and fixtures everywhere. A point of use unit protects one tap.
- Space. A softener needs room for two tanks, a drain and power, usually in a garage, utility closet or exterior pad. An under sink unit fits in a cabinet.
- Maintenance. A softener needs salt refills and an occasional cleaning of its brine tank. A filter needs cartridge changes on a schedule, and a reverse osmosis membrane is replaced less often.
- Water use. A softener sends water to the drain during regeneration, and a reverse osmosis unit sends a share of the incoming water to the drain while making pure water.
- Taste. Soft water can taste slightly salty or flat to some people. Reverse osmosis water tastes very clean, though some find it flat.
The sodium question
A salt based softener adds a small amount of sodium to the water, in proportion to the hardness removed. For most households this is unimportant, but people on a sodium restricted diet are advised to ask a physician, and many install a separate drinking tap that bypasses the softener or a reverse osmosis unit at the kitchen sink. Potassium chloride can replace sodium chloride as the regenerant, at a higher purchase cost, for households that want to avoid sodium.
Salt free conditioners
Another category goes by names such as scale conditioner or descaler. These devices do not remove minerals. Instead they alter the way calcium forms crystals, so the crystals stay suspended and are less likely to stick to surfaces. Claims about their performance vary, and results depend on the water and the installation. They need no salt and produce no waste water, which appeals to many owners, but they do not make water feel soft or reduce the soap needed, so they are a different product with a different outcome. Reading independent test information before choosing one is wise.
Local rules and wastewater
Some communities place limits on salt discharge from softeners because the brine ends up in the wastewater system and, eventually, in the groundwater or an irrigation supply. Rules differ, and a few areas restrict or prohibit certain types of regenerating softeners. Before buying, check with the water utility or the building department about local requirements. Demand controlled models, which regenerate based on actual water use rather than a fixed schedule, use less salt and less water than older timer based units, and they are widely recommended where discharge is a concern.
Testing the water first
Any decision should start with the actual water. A hardness test, from a kit or a lab, gives the level of minerals. The water supplier's annual report lists the hardness and other measured values. A test for iron, which stains fixtures orange, and for chlorine and total dissolved solids, helps decide what else is needed, since a softener has a limited ability to handle iron and none to address some other contaminants. Sizing is based on the hardness and the number of people in the house. An oversized unit regenerates too rarely and wastes resin, and an undersized one runs out of capacity and lets hard water through.
Where each one makes sense in a kitchen remodel
A remodel that adds a new dishwasher, an ice maker, a built in coffee machine and fine fixtures puts more equipment in the path of hard water, so protecting it makes financial sense. A whole house softener is a plumbing project that is best done by a licensed plumber when the supply lines are accessible. A point of use unit is easy to include during cabinet planning, with space reserved beneath the sink and a small extra faucet hole in the countertop or sink.
A common combination is a whole house softener for scale and a small reverse osmosis unit at the kitchen for drinking water, which gives protection everywhere and very clean water at the tap. A budget conscious household might begin with the part that matters most, whether that is the water heater and appliances or the glass of water in the hand.
Questions to settle before choosing
- How hard is the water, and what other contaminants does it carry?
- Is the main complaint scale on appliances, spotting on glass, taste or all three?
- Is there room for a tank, a drain connection and an outlet?
- Does the local utility restrict softener discharge?
- Does anyone in the household need to limit sodium?
- Who will refill the salt or change the cartridges, and how often?
Keeping it working
Whichever route is chosen, a treatment system works only if it is maintained. Salt must be kept above the water line in the brine tank, and hardened salt bridges that form a crust should be broken up. Cartridges should be replaced on the dates shown, and a flow check at the tap now and then catches a failing filter early. Keep the manual, and note the dates of service. Treating the water well protects the appliances and plumbing installed during a remodel and keeps the finished kitchen looking and working the way it did on the first day.