How Much Does a Reverse Osmosis System Cost in 2026?

How Much Does a Reverse Osmosis System Cost?

A reverse osmosis system costs $200 to $8,000 installed, depending mostly on the type you choose. A countertop unit sits at the low end. A whole-house system sits at the high end.

Here’s the full picture by system type:

Type of Reverse Osmosis System	Unit Cost	Installed Cost
Countertop	$200–$450	$200–$450 (no installation)
Under-sink with tank	$150–$350	$300–$700
Under-sink tankless	$300–$600	$450–$950
Whole-house	$4,500–$7,500	$4,800–$8,000

If you want better drinking and cooking water, start with an under-sink system. It costs a fraction of a whole-house setup and filters the tap you use most. Whole-house RO makes more sense if you’re on private well water with contaminants at every tap. Test your water first so you only pay for what you need.

You may see whole-house systems quoted for less, with some guides listing prices from about $1,000. Ask every installer whether the quote includes the storage tank, the pump, and any pretreatment. Lower quotes may leave those out.

Average Costs of Different Reverse Osmosis Systems

Each type of RO system suits a different home and budget. Here’s what you can expect to pay for each one.

Countertop reverse osmosis systems

Countertop systems cost $200 to $450. These portable units need no installation, so they work well for renters and small households. Price depends on the number of filtration stages and how well the unit is built.

Under-sink reverse osmosis systems with a tank

Under-sink systems with a storage tank cost $300 to $700 installed (the unit alone runs $150 to $350). The tank holds filtered water so it’s ready when you turn on the faucet. Most tank models produce 50 to 400 gallons per day, which fits many small and midsize households. The tradeoff is a wait for the tank to refill after heavy use.

Tankless reverse osmosis systems

Tankless under-sink systems cost $450 to $950 installed (the unit alone runs $300 to $600). They filter water on demand, so they take up less cabinet space. They also produce more, about 400 to 1,200 gallons per day, which suits homes with four or more people. Expect to pay roughly $150 to $250 more than a tank model.

Whole-house reverse osmosis systems

A whole-house system costs $4,800 to $8,000 installed. It connects to your main water line and treats every tap. A full setup includes the RO unit, a 150- to 500-gallon storage tank, and a pump. Price climbs with capacity:

System Size (Gallons per Day)	Unit Cost	Installed Cost
500	$4,500–$6,500	$4,800–$7,000
1,000	$5,000–$7,000	$5,300–$7,500
1,500	$5,500–$7,500	$5,800–$8,000

Whole-house RO costs many times more than an under-sink unit, and most households don’t drink or cook with water from every tap. It’s a good fit for homes on well water with several problems, or for households that want treated water at every faucet. Features like UV sterilization add to the total.

What Is a Reverse Osmosis System?

A reverse osmosis system is a type of water filtration system that uses pressure and a semipermeable membrane to remove contaminants from household water. You can buy one as a countertop, under-sink, or whole-house unit.

How reverse osmosis works

Water first passes through pre-filters that catch sediment and larger particles. Pressure then pushes it through a membrane with extremely small pores. Clean water passes through, and most dissolved contaminants stay behind. The system flushes those contaminants down the drain and sends the filtered water to your tap.

Here’s a quick look at that process:

What reverse osmosis removes

RO reduces dissolved solids, metals, and chemicals. That includes lead, arsenic, fluoride, nitrates, chlorine, pesticides, and PFAS (the “forever chemicals” found in some water supplies). It also strips out calcium and magnesium, which is why some systems add a remineralization stage.

Bacteria and viruses need a separate note. The membrane can block them, but home RO systems aren’t certified as microbiological purifiers. NSF International says the filters in RO systems protect against occasional contamination of water that’s already safe. If your well water tests positive for bacteria, you need a treatment certified for that, such as UV. Don’t rely on RO alone.

Benefits and drawbacks of reverse osmosis

Related: Compare Different Types of Water Treatment Systems

Factors That Affect Reverse Osmosis System Costs

Your home’s water quality shapes which system you need. More contaminants usually mean more filtration stages, and that raises the price.

System type and capacity

Type is the biggest price driver. Countertop and under-sink systems cost the least, and whole-house systems cost the most. Capacity matters too. Bigger households need systems that produce more gallons per day, and those cost more.

Filtration stages and efficiency

Most RO systems have three to seven filtration stages. Within the same brand, more stages usually mean a higher price. Efficiency counts as well. Newer high-efficiency models waste about one gallon for every gallon they filter, but they cost around $300 more than standard models.

Brand

Brand affects both price and features. Here’s what popular brands charge for residential countertop and under-sink units (unit only, before installation):

Brand	Unit Cost
Culligan	$1,000–$1,500
Brondell	$250–$450
iSpring	$200–$600
Home Master	$200–$600
Aquasana	$200–$250
Express Water	$150–$300
GE Pro Elite	$150–$230
Whirlpool	$150–$200

Culligan sells only through authorized dealers, and an under-sink model runs $1,050 to $1,700 installed. Dealers also rent systems for about $10 to $30 a month, with maintenance included.

Related: Best Reverse Osmosis System Brands of 2026

Certification

No federal rule requires certification for home RO systems. NSF/ANSI Standard 58 is the standard to look for on the label, because it verifies that the system performs as advertised. Certified systems often cost more, and the extra cost is worth it.

Water quality and pretreatment

Very hard water can call for a softener ahead of the RO unit. A softener costs $800 to $2,500 installed. A water test tells you whether you need one.

A water quality test can help you decide whether RO is the right fit. Home test kits cost $10 to $30, and laboratory testing costs $100 to $300.

Reverse Osmosis Installation Costs

Labor depends on system type, size, and how complicated your plumbing is. Plumbers typically charge $45 to $200 per hour.

Type of Reverse Osmosis System	Labor Cost
Countertop	None (no installation)
Under-sink	$150–$350
Whole-house	$300–$500 (up to $1,500 for complex jobs)

DIY vs. hiring a pro

If you have basic plumbing experience and a few common tools, you can install a countertop or under-sink system yourself. That saves about $150 to $300 in labor. A bad connection can cost you more than you saved, so be honest about your skill level.

Leave whole-house systems to a pro. They tie into your main water line, and a mistake can cause serious water damage. Hiring a pro also gets you a warranty on the work.

Questions to ask before you hire

• Will you test my water first to see whether I need pretreatment?
• Does the quote include the storage tank, pump, and drain line?
• Is the system NSF-certified?
• Do you offer a warranty on your labor?

Ongoing Costs of Reverse Osmosis Systems

An RO system costs money after you install it. Budget $50 to $250 a year for filters and upkeep. Once you add the extra water the system sends down the drain, total running costs can reach about $400 a year.

Ongoing Cost	Price	How Often
Replacement filters (under-sink)	$20–$100 per filter	Every six to 12 months
Replacement filters (whole-house)	$150–$250 each	Depends on water quality
RO membrane	$50–$100	Every two to five years
Water use	$0.03–$0.10 per filtered gallon	Ongoing
Repairs	$45–$450 on average (up to $800 for larger fixes)	As needed

Filters wear out faster when your tap water has more sediment, and systems with more stages need more filters. Water use depends on your local rates. Most under-sink systems drain four to five gallons for every gallon they filter, so a high-efficiency model can pay back its extra cost over time.

Additional Costs to Consider

• Pretreatment: A water softener for very hard water costs $800 to $2,500 installed.
• Drain connection: RO systems need a drain for wastewater, and a new drain line costs $300 to $800.
• Electrical work: A new outlet for a pump or whole-house system costs $150 to $350.
• Remineralization filter: Adding minerals back to your water costs $150 to $300.
• Plumbing repairs: Homes with older pipes may need plumbing repairs first.
• Old system removal: Taking out and disposing of an existing system costs $45 to $200.
• Water testing: Testing before and after installation confirms the system works.

Reverse Osmosis System Costs vs. Other Water Filtration Methods

RO costs more than most other filtration methods, but it also removes the widest range of dissolved contaminants. The ranges below are broad national figures. RO covers everything from a countertop unit to a whole-house setup, so see the sections above for costs by type.

Type of Water Filtration System	Average Cost
Reverse Osmosis (under sink)	$300 to $950
Reverse Osmosis (whole home)	$4,800 to $8,000
Well Water	$800 to $4,000
Activated Carbon	$180 to $1,400
Ionization	$400 to $1,900
U/V Light	$350 to $1,500
Water Softeners	$800 to $2,500

Return on investment

An under-sink system can pay off over time if you’d otherwise buy bottled water. Here’s our estimate of the 10-year cost, which adds the installed price to 10 years of filters and upkeep at $50 to $250 a year:

Under-Sink System	Installed Cost	Estimated 10-Year Cost
With tank	$300–$700	$800–$3,200
Tankless	$450–$950	$950–$3,450

That works out to roughly $7 to $29 a month, before the cost of water use. Compare that number with what you spend on bottled water today. Whole-house systems take much longer to pay off, and they rarely do unless your water has problems that need treating at every tap.

Environmental impact

An RO system can cut the plastic bottles you buy and throw away. It also sends water down the drain, up to five gallons for every gallon you drink. If that bothers you, choose a high-efficiency model or install RO at a single tap instead of the whole house.

Tips for Saving Money on a Reverse Osmosis System

RO has a high upfront cost, but a few choices can bring your total down.

Test your water first

A $10 to $30 test kit shows what’s in your water. You can skip filtration stages and add-ons you don’t need.

Start with an under-sink system

If you mainly want better drinking water, an under-sink unit does the job for $300 to $950 installed. A whole-house system costs $4,800 to $8,000.

Compare quotes

Installation prices vary by company. Get at least three written quotes, and make sure each one covers the same equipment and work.

Install a simple system yourself

Doing a countertop or under-sink install yourself saves about $150 to $300 in labor. Skip this for whole-house systems.

Consider a refurbished unit

A refurbished system costs less upfront. Confirm it’s in good condition and still covered by a warranty.

Think twice about renting

Renting a system at $10 to $30 a month sounds cheap. Over 10 years, it adds up to $1,200 to $3,600, which can match or beat the cost of buying.

Change filters on schedule

Replacing filters on time protects the membrane, which is the most expensive part to replace.

Reverse Osmosis System Cost FAQs

Find a Reverse Osmosis System Installer

Ready to move forward? Use Modernize’s pro finder tool to receive competitive quotes from local installers, or explore our list of the Best Water Treatment Companies to compare trusted providers.

Sources

• HomeGuide, reverse osmosis system cost
• Angi, reverse osmosis water filter cost
• This Old House, reverse osmosis system cost (2026)
• Thumbtack, reverse osmosis system installation cost
• HomeAdvisor, reverse osmosis system cost (2025)
• NSF, standards for water treatment systems (NSF/ANSI 58)
• Water Quality Association, boil water notice study