Reverse Osmosis System Cost: 2025 Complete Installation Price Guide
Reverse osmosis is the gold standard for residential water purification — the only filtration technology that removes the widest spectrum of contaminants from drinking water, including lead, arsenic, PFAS, nitrates, and fluoride. Reverse osmosis system cost ranges from $150 for a basic DIY under-sink unit to $5,000 or more for a professionally installed whole-house system. The most common setup — a 5-stage under-sink RO system installed by a licensed plumber — averages $300 to $800 all-in. This guide breaks down every cost variable: system type, installation labor, ongoing filter maintenance, water waste, and whether an RO system is genuinely worth it for your home.
If you decide to move forward with an RO installation, you can use RateYourPlumber.com to find licensed plumbers in your area with verified reviews from real customers who had the same work done. Comparing two or three local contractors before booking can save you $100 to $300 on a standard under-sink RO installation.
Reverse Osmosis System Cost Overview
The table below covers the full range of reverse osmosis system types — from basic under-sink units to commercial-grade systems — with average installed costs and typical price ranges. All figures include the unit, standard installation labor, and required fittings.
| System Type | Average Cost (Installed) | Cost Range |
|---|---|---|
| Under-sink RO (3-stage) | $300 | $150 – $500 |
| Under-sink RO (5-stage) | $500 | $300 – $800 |
| Under-sink RO with remineralization | $600 | $400 – $1,000 |
| Whole-house RO system | $2,500 | $1,500 – $5,000 |
| Commercial RO system | $5,000 | $2,000 – $15,000+ |
| Annual filter replacement cost | $100 | $50 – $200 |
| Membrane replacement (every 2–3 yrs) | $75 | $50 – $150 |
Note: Unit cost alone ranges from $50 to $500+ depending on the brand and stage count. Labor to install an under-sink RO system typically adds $150 to $300. Whole-house systems require larger-diameter plumbing connections and may need a booster pump, pushing labor to $500 to $1,500. Costs vary by region — high-cost metros like San Francisco, Boston, and New York City run 25 to 40 percent above national averages.
How Reverse Osmosis Works
Reverse osmosis uses pressure to force water through a semipermeable membrane with pores so small — typically 0.0001 microns — that dissolved contaminants, heavy metals, salts, and most organic compounds cannot pass through. What passes through the membrane is called permeate (clean water); what is flushed away is called concentrate or brine (contaminated reject water).
The Stages of RO Filtration
Most residential under-sink systems use a 4 to 6 stage process:
- Sediment pre-filter (Stage 1): Removes particles, rust, dirt, and suspended solids larger than 5 microns. Protects the membrane from clogging and premature wear.
- Carbon block pre-filter (Stage 2): Removes chlorine, chloramines, volatile organic compounds (VOCs), and taste/odor compounds. Chlorine degrades RO membranes — this stage protects the core of the system.
- Granular activated carbon (Stage 3): Second carbon pass for additional organic compound removal. Some 3-stage systems combine stages 2 and 3.
- RO membrane (Stage 4): The core. Removes dissolved solids, heavy metals, fluoride, nitrates, arsenic, PFAS, and most ionic contaminants. Typical TDS reduction: 90 to 99 percent.
- Post-filter/polishing carbon (Stage 5): Final taste and odor polishing after the storage tank. Removes any residual taste from the tank or lines before water reaches the faucet.
- Remineralization stage (optional Stage 6): Adds back calcium, magnesium, and trace minerals that the membrane strips out. Addresses the flat taste of fully demineralized water and adds alkalinity.
TDS Reduction: What It Means
TDS stands for Total Dissolved Solids — the aggregate concentration of all dissolved minerals, metals, and salts in your water, measured in parts per million (ppm). Tap water in the United States typically tests at 100 to 500 ppm TDS. A quality RO membrane reduces this by 90 to 99 percent, producing water at 10 to 30 ppm TDS — comparable to premium bottled water.
TDS reduction does not tell the whole story. A system can produce low-TDS water while still passing specific contaminants if the membrane has degraded or if the contaminant bypasses the membrane (as fluoride does at a small percentage without a quality membrane). Test your water before and after installation to confirm actual contaminant reduction for your specific supply.
Water Waste: The Reject Water Reality
Every RO system produces reject water — the concentrated brine that flushes contaminants down the drain. Traditional RO systems produce 3 to 4 gallons of waste water for every 1 gallon of clean water (a 3:1 or 4:1 waste ratio). Modern high-efficiency systems have improved this significantly: premium units achieve 1:1 or even better ratios using permeate pumps, pressurized recirculation, or tankless designs. If water conservation is a priority in your household, look for systems rated at 2:1 or better waste ratio — they cost more upfront ($300 to $600 for the unit alone) but reduce drain usage substantially over time.
Under-Sink vs. Whole-House RO Systems
The single biggest decision in purchasing an RO system is whether you want point-of-use filtration (treating water at one faucet) or whole-house filtration (treating every water source in the home). Here is how they compare:
| Feature | Under-Sink RO | Whole-House RO |
|---|---|---|
| What it treats | Drinking and cooking water at one dedicated faucet | All water in the home: drinking, bathing, laundry, irrigation |
| Average installed cost | $300 – $800 | $1,500 – $5,000 |
| Flow rate | 50 – 100 GPD (fills glass slowly; tank stores supply) | 500 – 3,000+ GPD (supports whole home demand) |
| Water waste ratio | 2:1 – 4:1 (standard); 1:1 (high-efficiency models) | 3:1 – 6:1 (higher volume means more waste) |
| Installation complexity | Low — connects to cold water supply line and drain under sink | High — connects to main supply line; requires booster pump, large storage tank, re-pressurization |
| Best for | Homes with acceptable water except for drinking quality; budget-conscious buyers | Homes with serious contamination issues (arsenic, nitrates, PFAS in supply), well water, areas with severe water quality concerns |
| Annual maintenance cost | $100 – $200 (filters + membrane) | $300 – $600 (larger filters, higher membrane replacement cost) |
| Permit typically required? | No (in most jurisdictions) | Often yes — connects to main supply line |
For most households, an under-sink 5-stage RO system hitting the kitchen drinking water and a refrigerator line is the correct solution. Whole-house RO is reserved for situations where the contamination risk justifies treating all water sources — most commonly with private well water, agricultural runoff contamination, or known PFAS plume exposure in the municipal supply.
What Does Reverse Osmosis Remove?
RO is the most comprehensive residential water treatment technology available for dissolved contaminants. The semipermeable membrane physically blocks dissolved ions and molecules — which means it works on contaminants that activated carbon and standard filters cannot touch.
What RO Removes
- Lead: 95 to 98 percent removal. The most critical reason many families choose RO, particularly in homes with older plumbing or lead service lines. The EPA has no safe level of lead for children.
- Arsenic: 90 to 95 percent removal. A naturally occurring contaminant in well water in many parts of the U.S. (New England, the West, and the Great Plains). Standard carbon filters do not remove arsenic.
- Fluoride: 85 to 92 percent removal. Fluoride is a small, negatively charged ion. A quality RO membrane removes the majority of it, though not 100 percent. Some parents choose RO specifically to control fluoride intake; others specifically want fluoride retained (consult your dentist about supplementation needs).
- Nitrates and nitrites: 83 to 92 percent removal. Critical for infants and pregnant women. Nitrate contamination from agricultural runoff is common in rural well water and some municipal supplies. RO is EPA-recommended for nitrate removal.
- PFAS (per- and polyfluoroalkyl substances): 70 to 94 percent removal depending on compound and membrane quality. PFAS ("forever chemicals") contamination is increasingly detected in U.S. water supplies. NSF/ANSI 58-certified RO membranes are tested specifically for PFAS reduction. This is one of the most compelling reasons to install RO in areas with known PFAS contamination.
- Chlorine and chloramines: Near-complete removal by the carbon pre-filter stage (not the membrane itself). Chlorine is the primary driver of the "tap water taste" most people dislike.
- Chromium-6: 85 to 95 percent removal. Hexavalent chromium is a known carcinogen found in some municipal supplies.
- Dissolved salts (sodium, sulfates, etc.): 90 to 99 percent removal. Key for people on sodium-restricted diets or in areas with high-sodium groundwater.
- Radium and uranium: 85 to 95 percent removal. Present in well water in granite-heavy geologic regions.
- Pharmaceuticals and hormones: 90 to 99 percent removal for most compounds. Growing concern as pharmaceutical residues enter municipal water supplies through wastewater reuse.
- Bacteria and viruses: Largely removed by the membrane, but RO is not certified as a standalone disinfection system. Pair with UV if microbial safety is the primary concern.
What RO Does NOT Remove
- Some volatile organic compounds (VOCs): Dissolved gases and some low-molecular-weight VOCs can pass through the membrane. The carbon pre-filter removes most chlorine-based VOCs, but dissolved gases like radon or hydrogen sulfide require additional treatment (aeration or catalytic carbon).
- Minerals entirely (in standard systems): A fresh RO membrane also strips beneficial minerals like calcium and magnesium. The resulting water is "dead" tasting and slightly acidic. Remineralization systems (Stage 6) add these back. If you skip remineralization, the soft water is safe to drink but may taste flat.
- All pesticides: Activated carbon handles most pesticides, but some pass through both carbon and the membrane. If agricultural chemical runoff is your concern, test your water for specific pesticide panels and confirm the RO system is NSF 58 certified for those compounds.
Reverse Osmosis System Installation Cost Breakdown
Understanding what drives installation cost helps you evaluate quotes and identify legitimate line items versus padding. Here is the full cost breakdown for a standard under-sink 5-stage RO installation:
| Cost Component | Average Cost | Notes |
|---|---|---|
| RO unit (5-stage) | $150 – $350 | Retail cost of the system itself. Brands: APEC, iSpring, Home Master, Waterdrop. NSF 58 certification matters. |
| Dedicated RO faucet | $30 – $150 | Most systems include a basic faucet. Premium brushed nickel or air-gap faucets cost more. Requires a hole in the sink deck or countertop. |
| Storage tank | $40 – $100 | Standard 3-gallon tank is usually included. Upgrade to 4- or 5-gallon for higher household demand. |
| Drain connection (saddle valve) | $10 – $30 | Connects the reject water line to the drain. Some plumbers prefer a proper drain air-gap fitting over a saddle valve — ask about local code requirements. |
| Supply line connection | $15 – $40 | Tee fitting into the cold water supply line under the sink. Angle stop included in most kits. |
| Refrigerator line connection (optional) | $50 – $150 | Run a 1/4-inch supply line from the RO tank to the fridge ice maker/water dispenser. Requires routing tubing behind cabinets. |
| Booster pump (if needed) | $60 – $150 | Required if your home water pressure is below 40 PSI. Low pressure dramatically reduces RO output and membrane life. |
| Installation labor | $100 – $300 | Standard under-sink install takes 1 to 2 hours for a licensed plumber. Includes all connections, mounting, leak testing, and system flush. |
| Permit | $0 – $75 | Under-sink point-of-use installations rarely require permits. Whole-house connections to the main line may require a plumbing permit. Check with your local building department. |
Total Installed Cost Estimates by Scenario
- DIY under-sink 5-stage system: $150 to $350 (unit + fittings only; no labor)
- Plumber-installed 5-stage under-sink: $300 to $700
- Plumber-installed with remineralization + refrigerator line: $500 to $900
- Tankless (no-storage) RO system installed: $400 to $800
- Whole-house RO system installed: $1,500 to $5,000 depending on flow rate, booster pump, and storage tank size
DIY vs. Professional Installation: Which Is Right for You?
Under-sink RO systems are among the more accessible DIY plumbing projects. All connections use push-to-connect or compression fittings — no soldering, no gluing, no cutting of existing hard plumbing required. The tools needed are a drill (for the dedicated faucet hole if your sink does not have an existing knockout), a basin wrench or channel-locks, and a measuring tape. The entire process takes 1.5 to 3 hours for a first-timer following the manufacturer instructions carefully.
Where professional installation makes sense: if you want the refrigerator line connected (running tubing through cabinets gets fiddly), if you have tile or stone countertops requiring a core drill for the faucet hole, if your home has copper supply lines requiring compression fittings, or if you simply want a plumber to verify the installation is leak-free and the system is performing correctly before you trust it for drinking water. A professional installation also gives you a licensed contractor to call back if the system develops a leak.
Ongoing Costs: Filters, Membrane, and Water Waste
The upfront cost of an RO system is only part of the total cost of ownership. Every RO system requires regular filter and membrane replacement to maintain performance — and every system wastes some water. Here is what ongoing ownership actually costs per year.
Filter Replacement Schedule and Cost
| Filter/Component | Replacement Interval | Cost per Replacement | Annual Cost |
|---|---|---|---|
| Sediment pre-filter (Stage 1) | Every 6 – 12 months | $8 – $20 | $10 – $40 |
| Carbon block pre-filter (Stage 2) | Every 6 – 12 months | $15 – $30 | $20 – $60 |
| GAC carbon filter (Stage 3) | Every 6 – 12 months | $10 – $25 | $15 – $50 |
| RO membrane (Stage 4) | Every 2 – 3 years | $30 – $100 | $15 – $50 (annualized) |
| Post-carbon polishing filter (Stage 5) | Every 12 months | $10 – $25 | $10 – $25 |
| Remineralization cartridge (if applicable) | Every 6 – 12 months | $15 – $40 | $20 – $80 |
Total annual maintenance cost: approximately $70 to $200 per year for a typical household (2 to 4 people) using the system primarily for drinking and cooking water. Most manufacturers sell annual filter subscription kits for $50 to $120 that bundle all replacement filters at a discount versus buying them individually.
Water Waste Cost Calculation
A household using an RO system for drinking and cooking water typically produces 1 to 3 gallons of purified water per day. At a 3:1 waste ratio, that means 3 to 9 additional gallons go down the drain daily. At the U.S. average water rate of approximately $0.004 per gallon (0.4 cents per gallon), the annual cost of RO reject water is roughly $4 to $13 per year — negligible for most households. Even at a 4:1 ratio with heavy use, the annual water waste cost is under $20. This is frequently overstated as a reason not to buy an RO system; the financial impact is minor.
True Annual Cost of Ownership Compared to Bottled Water
The average American household that buys bottled water for drinking spends $400 to $800 per year on single-use plastic bottles, assuming 1 to 2 bottles per person per day for a family of four at $1 to $2 per bottle. An RO system installed for $500 and maintained at $100 per year pays back its installation cost in year one versus continued bottled water purchases — and every subsequent year saves the full bottled water budget minus $100 in filter costs. Over 5 years, the math is decisive: RO ownership costs $1,000 total versus $2,000 to $4,000 in bottled water over the same period.
RO vs. Other Water Filtration Types
Reverse osmosis is not the only residential water treatment option. Different filter technologies remove different contaminants at different costs. Here is how RO stacks up against the three most common alternatives:
| Technology | What It Removes | What It Does NOT Remove | Installed Cost | Annual Maintenance | Best For |
|---|---|---|---|---|---|
| Reverse osmosis (RO) | Lead, arsenic, fluoride, nitrates, PFAS, dissolved salts, most heavy metals, bacteria | Some VOCs, dissolved gases, 100% of fluoride | $300 – $800 (under-sink) | $100 – $200/yr | Comprehensive contaminant removal; known heavy metal/PFAS exposure; well water; replacing bottled water |
| Activated carbon filter (pitcher or under-sink) | Chlorine, chloramines, VOCs, some pesticides, taste and odor | Lead (unless certified), fluoride, nitrates, arsenic, dissolved salts, heavy metals | $30 – $300 | $30 – $80/yr | Taste and odor improvement; chlorine removal; low-contamination municipal water |
| UV (ultraviolet) purifier | Bacteria, viruses, protozoa, cysts (99.99% kill rate) | Chemical contaminants, heavy metals, dissolved solids, fluoride, nitrates — nothing chemical | $200 – $600 | $50 – $100/yr (bulb replacement) | Microbiological safety; well water with bacteria/coliform concerns; no chemical contamination |
| Water softener (ion exchange) | Calcium, magnesium (hardness); some heavy metals in cation exchange | Fluoride, nitrates, PFAS, arsenic, bacteria, chlorine — does not purify, only softens | $700 – $2,000 | $100 – $200/yr (salt) | Hard water scale prevention; appliance protection; skin and hair improvement; does NOT make water safer to drink |
The critical insight: Water softeners and RO systems solve different problems and are frequently installed together. A water softener treats the hardness that clogs pipes and damages appliances throughout the house; an RO system at the kitchen sink then removes the residual sodium added by the softener's ion exchange process, along with any additional drinking-water contaminants. This combination — whole-house softener plus under-sink RO — is the most comprehensive residential water treatment setup for most problem water scenarios.
Is Reverse Osmosis Worth It?
The answer depends on your water quality, your health priorities, and your household economics — but for most families considering RO, the answer is yes. Here is the honest analysis:
The Case For RO
- Financial ROI vs. bottled water: If your household currently buys bottled water, an RO system pays for itself in 6 to 18 months. Ongoing filter cost of $100 per year versus $400 to $800 per year in single-use bottles is a clear economic win, with no plastic waste and no hauling cases from the store.
- Known contamination in your supply: If your municipality or well water tests positive for lead, arsenic, PFAS, or nitrates above EPA action levels, RO is not optional — it is the appropriate response. No carbon filter, softener, or UV unit matches RO's documented performance on these contaminants.
- Peace of mind for vulnerable household members: Households with infants, pregnant women, or immunocompromised individuals have disproportionate stakes in drinking water purity. The EPA's maximum contaminant levels (MCLs) are set for average healthy adults — not for the most vulnerable. RO provides an extra margin of safety that most households consider worthwhile.
- Water quality in areas with aging infrastructure: Lead service lines remain in an estimated 6 to 10 million U.S. homes. Even if your municipal water tests clean at the treatment plant, lead can leach into the water at your tap. An under-sink RO system specifically protects the water you drink and cook with.
The Honest Cons
- Removes beneficial minerals: A standard RO system removes calcium and magnesium along with contaminants, producing water that is slightly acidic and low in minerals. For most adults with a varied diet, this is not clinically significant — you get far more calcium from food than from water. But if you prefer mineralized water for taste or health reasons, add a remineralization stage ($30 to $80 for the filter cartridge).
- Slow flow rate from the dedicated faucet: An RO storage tank fills at 50 to 100 gallons per day. If you empty the 3-gallon tank (by filling a cooking pot or water pitcher), you wait 30 to 45 minutes for it to refill. Tankless systems address this with faster membranes (400+ GPD), but cost more upfront ($300 to $600 for the unit).
- Waste water: Traditional systems discharge 3 to 4 gallons for every gallon produced. As discussed above, the actual dollar cost of this waste is small (under $15 per year), but it is a real tradeoff if water conservation is a priority.
- Ongoing filter discipline: An RO system with expired filters performs poorly and can harbor bacteria in saturated carbon media. Filter replacement is not optional — it is the price of ownership. If you cannot commit to annual filter changes, a certified carbon pitcher filter is better than a neglected RO system.
Who Should Definitely Buy an RO System
- Households with private well water that has not been professionally tested recently
- Homes built before 1986 with possible lead service lines or lead solder in plumbing
- Families spending $40 or more per month on bottled water
- Anyone in an area with documented PFAS, nitrate, or arsenic contamination in their municipal supply (check your annual Consumer Confidence Report from your water utility)
- Households with infants or pregnant women where nitrate and lead exposure risk is elevated
Who Might Not Need RO
- Households already on an effective whole-house carbon filtration system with tested water quality at acceptable levels
- Renters who cannot install under-sink plumbing — a countertop RO unit ($200 to $400) is a more practical alternative
- Households whose only concern is taste/odor from chlorine — a $30 to $60 activated carbon pitcher filter handles that without the full RO cost
How to Find a Plumber to Install an RO System
Installing an under-sink RO system is one of the simpler plumbing jobs a licensed plumber handles — but that does not mean all plumbers are equal at it, and it does not mean pricing is uniform. Here is how to find the right person for the job and make sure you are not overpaying.
What to Look for in an RO Installation Plumber
- Plumbing license: Verify the contractor holds an active plumbing license in your state. In most states this is publicly searchable on the contractor licensing board website. RO installation involves modifications to your home's water supply system — unlicensed work on that system may void your homeowner's insurance coverage for water damage.
- Experience with RO systems specifically: Not every plumber installs RO systems regularly. Ask: "Have you installed reverse osmosis systems before? What brands do you prefer?" A plumber who installs RO weekly will be faster, more confident with the fittings, and better at troubleshooting than one who does it twice a year.
- Flat-rate quote for the specific job: A straightforward under-sink RO installation should be quotable over the phone. Get a firm price that includes labor, all fittings, and the faucet hole if you need one drilled. Beware of any contractor who refuses to quote until they see the job in person — for a standard under-sink install, this is unnecessary and often a sign of pricing that expands on-site.
- Verified customer reviews: Check what past customers say about the quality of water filtration work specifically, not just general plumbing. On RateYourPlumber.com, you can read verified reviews from homeowners in your area who hired specific plumbers for exactly this type of work.
What a Good RO Installation Includes
When a licensed plumber finishes an under-sink RO installation, you should receive: a fully connected system with the dedicated faucet mounted and operational, a drain saddle valve (or proper air-gap drain fitting) connected and leak-free, a cold-water supply connection with an angle stop shutoff valve, the storage tank installed and pressurized (typically 6 to 8 PSI pre-charge), all supply lines flushed and sanitized per manufacturer instructions, a TDS reading confirming the membrane is performing, and verbal guidance on the filter replacement schedule. If the plumber does not perform a TDS test before leaving, ask for one — it confirms the system is working correctly from day one.
Ready to get quotes? Use RateYourPlumber.com to find licensed plumbers in your area with ratings and reviews from verified customers. Comparing two or three quotes for an RO installation typically takes under an hour and routinely saves homeowners $100 to $300 on a job of this size.
Frequently Asked Questions
How much does a reverse osmosis system cost?
A reverse osmosis system costs between $150 and $800 installed for a standard under-sink 5-stage unit. The unit itself ranges from $50 to $350 at retail; professional installation adds $100 to $300 in labor. A 3-stage under-sink system averages $300 installed; a 5-stage system averages $500 installed; a system with remineralization averages $600. Whole-house RO systems cost significantly more — $1,500 to $5,000 installed — because they require larger membranes, booster pumps, and large storage tanks connected to the main supply line. Annual maintenance (filter replacement) adds $100 to $200 per year to the total cost of ownership.
Is reverse osmosis worth the cost?
Yes, for most households — especially those currently buying bottled water or living in areas with known water quality issues. A $500 installed RO system produces water that tests comparably to premium bottled water at roughly $0.01 per gallon (accounting for filter costs), versus $1 to $2 per bottle for single-use plastic. A family of four spending $50 per month on bottled water recovers the full RO installation cost in 10 to 12 months. Beyond economics, RO is the most effective residential technology for removing lead, arsenic, PFAS, fluoride, and nitrates — contaminants that carbon filters, water softeners, and UV systems do not reliably address. If anyone in your household is an infant, pregnant, or immunocompromised, the case for RO is even stronger.
What does reverse osmosis remove from water?
Reverse osmosis removes a broader range of contaminants than any other single residential filtration technology. A quality 5-stage RO system removes lead (95 to 98 percent), arsenic (90 to 95 percent), fluoride (85 to 92 percent), nitrates and nitrites (83 to 92 percent), PFAS per- and polyfluoroalkyl substances (70 to 94 percent), chromium-6, dissolved salts, radium, uranium, pharmaceuticals, and most bacteria and viruses. Chlorine and chloramines are removed by the carbon pre-filter stages before the membrane. RO does not remove all volatile organic compounds or dissolved gases — and a standard RO membrane also removes beneficial minerals like calcium and magnesium (which a remineralization stage can add back).
How long do reverse osmosis filters last?
The pre-filters (sediment and carbon stages) in a reverse osmosis system typically last 6 to 12 months depending on your water quality and daily usage volume. The RO membrane — the core of the system — lasts 2 to 3 years under normal use. The post-filter polishing carbon cartridge lasts 12 months. A remineralization cartridge, if present, also needs replacement every 6 to 12 months. Harder water, high sediment content, or heavy daily use shortens all filter lifespans. Most manufacturers include a TDS meter with the system so you can test the output water quality — a significant rise in TDS (above 30 to 50 ppm from a previously low baseline) is a reliable indicator that the membrane needs replacement regardless of the calendar.
Can I install a reverse osmosis system myself?
Yes. Under-sink reverse osmosis systems are designed for DIY installation and use push-to-connect or compression fittings throughout — no soldering, no gluing, and no modification of hard plumbing is required. The tools needed are basic: a drill with a hole saw for the dedicated faucet (if your sink has no existing pre-drilled hole), channel-lock pliers, and a bucket to catch water during connections. The full installation takes 1.5 to 3 hours for a first-timer following the included instructions carefully. The most common DIY errors are an overtightened drain saddle that cracks the drain pipe, forgetting to flush the system for 2 full tank cycles before drinking the water, and incorrect tank pre-charge pressure. If you are not comfortable drilling into your sink deck, or if your countertop is tile or stone, hire a plumber for at least the faucet hole portion of the job.
Does reverse osmosis remove fluoride?
Yes. A reverse osmosis membrane removes approximately 85 to 92 percent of fluoride from water. Fluoride is a small, negatively charged ion (fluoride anion, F-) that most filters cannot touch — activated carbon does not remove fluoride, and water softeners do not remove fluoride. The RO semipermeable membrane physically blocks fluoride ions at the 0.0001-micron level. The removal rate is not 100 percent because fluoride is a very small ion; some passes through even the best membranes. If fluoride removal is your primary reason for purchasing an RO system, look for a system tested and certified under NSF/ANSI Standard 58 specifically for fluoride reduction. For most families, the 85 to 92 percent reduction brings fluoride levels well below EPA's maximum contaminant level of 4 mg/L and secondary standard of 2 mg/L.