Whole House or Under the Sink Filtration System: Which Do You Need?

A whole-house water filtration system treats a specific water quality problem, like chlorine or iron. A reverse osmosis drinking water filtration system, which is generally installed under your sink, treats a variety of issues ranging from odors and tastes to potential health concerns.

Do you need a whole-house or under-sink filtration system? This guide will help you decide.

Drinking Water Filtration Systems

For cleaner, safer, great-tasting drinking water, consider an under-the-sink water filter.

Perhaps your focus is on safeguarding your family from potential contaminants in your drinking water or addressing aesthetic issues like taste, odor or appearance.* Your water may be discolored, cloudy, salty or bitter, or even have a metallic taste. Maybe it just doesn’t smell right — or perhaps you’ve heard reports of potential safety issues with your local water supply.

In these cases, installing an undersink water filtration system — specifically, a reverse osmosis drinking water filtration system (RO) — is an excellent solution. Reverse osmosis systems are one of the best ways to treat water for a wide variety of issues and concerns. They work by using multiple stages of filtration to reduce impurities and make water taste crisp and fresh. Their filtration capabilities are more advanced than those of standard pitcher filters, tap filters or refrigerator filters.

For example, Culligan’s Aquasential® reverse osmosis systems are certified to reduce more than 90 contaminants — including those you can see and taste as well as those you can’t, such as bacteria, lead, mercury and volatile organic compounds (VOCs). Culligan RO systems also can remove up to 95% of dissolved salts, metals and minerals in your water (known as total dissolved solids, or TDS). That’s why undersink filters like these are the preferred option for cleaner, safer, great-tasting drinking water.

Whole House Water Filtration Systems

For water issues that cause problems when cleaning, bathing and washing in addition to drinking, consider a whole house filtration system.

A whole home filtration system treats water from the point where it enters the home, so it provides better-quality water from every faucet and shower. These systems are most often needed to address problem water that impacts you throughout your home — and they’re a common solution for well water issues.

You can purchase whole house filter systems designed to reduce the rotten egg smell produced by sulfur, for example, or to reduce floating, sand-like particles in your water. Other home water filters can target high levels of chlorine that may leave water smelling like bleach, or the excess amounts of iron that cause red or brown staining in sinks, showers, tubs and toilets or leave rust-colored stains on laundry.

You can also use whole-home options to reduce other contaminants that are specific to your geographic area or water supply, including arsenic. You can’t see, taste or smell these impurities, but a water test can reveal if they’re in your water.

Bonus: Water Softener

For hard water problems affecting your skin, dishes, appliances and fixtures, consider a water softener.

If you’re seeing limescale buildup on shower heads, faucets and shower doors, you likely have what’s known as hard water. This hardness comes from high concentrations of minerals, mostly calcium and magnesium. Problems typically arise throughout your home — and with your hair and skin as well — when these minerals build up over time.

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Hardness may also be to blame, for example, if soaps are leaving a filmy residue on your skin and hair, if your clothes are scratchy after you wash them or if you see spots on just-cleaned dishes. Hard water even impairs the efficacy of water-using appliances like coffee makers and water heaters, and it can shorten their lifespan over time. It also causes increased spending on soaps and detergents.

Hard water is a common problem for those who get their water from private wells, but it can also be a burden for customers of municipal water supplies. Fortunately, water softeners can remove the minerals that cause hardness. They’re installed at your water source, so you can have soft water throughout your home.

Combining Water Treatment Solutions

To solve multiple water quality issues, consider a combination of solutions.

Sometimes a single product doesn’t solve all the water woes of a household. Purchasing both a water softener and whole house filtration system is useful if your water is hard and also smells like rotten eggs, for instance (a common combination for well water).

If your water is high in chlorine but you also have concerns about potential contaminants in your drinking water, you can combine a whole house water filter system with a reverse osmosis under-sink filter system. Or, if your water has high levels of hardness but your drinking water also has an unpleasant taste or odor, you may choose to use a water softener as well as an RO system.

Rest assured that a local water treatment expert can help you discover the source of your home’s specific water issues and tailor a solution to treat them most effectively. With so many high-performance systems available today that are designed to provide high-quality water throughout your home, it doesn’t have to be complicated — or costly — to get water you can trust.

Undersink vs. Whole Home Filtration Systems: FAQs

Is Whole House Water Filtration Better Than Under-Sink?

Whole home filtration isn’t necessarily better than undersink drinking water filtration. Each whole home system treats one specific problem, like chlorine or iron, in all the water that flows into your home. Under-the-sink filtration only addresses your drinking water, but it can treat a wider variety of problems, including bacteria, lead, microplastics and more.

Is a Whole House Water Filtration System Worth It?

A whole house filtration system is worth it if you want to treat a specific problem like chlorine odors or iron stains throughout your home. These systems provide filtered water at every tap.

What Are the Disadvantages of an Undersink Water Filter?

The main disadvantage of an under-the-sink system is that it only treats your drinking water. While it can address a variety of potential water problems, it doesn’t address water at your bathroom sinks, showerhead or other taps.

What Is the Best Water Filtration Method for a Home?

The best water filtration method for your home depends on your specific water problems. Whole house systems are better for specific issues, while drinking water filtration systems are a good way to address multiple contaminants.

*Contaminants may not be in your water.