What you'll need
- RO system type — under-sink, countertop, whole-house, or tankless
- Brand tier — budget, mid-range, or premium
- Water source — city/municipal or well water
- Daily gallon usage for drinking and cooking
What you'll get
- Installation cost — Equipment plus labor estimate
- Annual filter cost — Ongoing replacement expense
- Cost per gallon — Amortized over 5 years
- Bottled water comparison — Payback period vs. buying bottled
RO System Cost by Type
| Type | Install Cost |
|---|---|
| Under-Sink | $300–$950 |
| Multi-stage / premium under-sink (Under-Sink, Premium tier) | $500–$1,500 |
| Whole-House | $4,800–$8,000 |
Under-sink vs. whole-house — and running costs
An under-sink RO ($300–$950 installed) treats drinking/cooking water at one tap — right for most homes. A whole-house RO ($4,800–$8,000) treats every tap and is a much bigger job needing a drain line and often electrical.
Ongoing cost: pre/post filters run $50–$100/year; the RO membrane lasts 2–5 years ($50–$150). RO wastes 3–4 gallons per gallon produced — a permeate pump cuts that. Even so, it's far cheaper per gallon than bottled water.
Questions to ask, red flags & warranty
- How many stages, and is remineralization included (RO strips minerals)?
- What's the daily GPD output and the pure-to-waste ratio?
- Is drain and faucet install included? (A leaky drain saddle is the most common callback.)
Warranty: quality systems carry 1–5 year warranties on the unit; keep the model/filter records so replacements fit.
Reverse osmosis does not soften your water
These two get bought interchangeably and they solve different problems. RO is point-of-use filtration: it makes the water at one tap clean enough to drink. It does nothing about the hard water reaching your shower, your laundry or your water heater — and in fact very hard water shortens an RO membrane's life, which is why some installers want a softener upstream of one. If limescale, dull laundry and soap that will not lather are the actual complaint, a softener is the right purchase: the water softener installation cost calculator sizes one from your household and water hardness and prices it from there.
Under-sink reverse osmosis runs $300–$950 installed and is the common case. The calculator's whole-house path returns the published installed range of $4,800–$8,000 on city water, and $5,100–$8,300 with a hard-well pretreatment surcharge; brand tier and local labor rate do not move it, because the source publishes one installed range rather than a unit and labor split.
How this calculator builds the installed price
Each system type has its own unit-cost and labor bands by brand tier — budget, midrange or premium — and labor is further scaled by a location multiplier (low-cost 0.85x, average 1.0x, high-cost 1.25x). Well water adds a flat surcharge on top: $150 for a standard well, $300 for hard well water that needs pre-treatment.
Switch that same job to a well with hard water in a high-cost location and the labor band alone moves to $125–$250 (×1.25), plus a $300 surcharge — pushing the total to $725–$1,100 for the identical unit.
How the whole-house path is priced, and what moves it
The whole-house path does not build its price from unit and labor rows. It returns the dataset's published installed range for whole-house reverse osmosis (Angi, retrieved 2026-07-13), the same $4,800–$8,000 this page's cost table shows. At the default inputs (city water, 5 gallons a day) the result is $4,800–$8,000. Switching to hard well water in a high-cost location adds only the $300 pretreatment surcharge and returns $5,100–$8,300, which is the highest total the calculator can output for this system.
Because the source gives one installed range, the brand-tier and labor-market inputs are ignored on this path; the breakdown row says so rather than implying a labor split was costed. Under-sink is different: at midrange on city water and average labor it returns $400–$750, and at the premium tier $700–$1,200, which sits inside the table's "Multi-stage / premium under-sink" band of $500–$1,500. The multi-stage row is the Under-Sink option at the Premium tier; there is no separate multi-stage system type to select.
What the cost-per-gallon figure actually compares
This calculator also returns a cost-per-gallon figure and a bottled-water comparison, both built from your stated daily usage. It amortizes the installed cost over five years, adds the system's annual filter-replacement cost (which ranges from $40/yr for a countertop unit to $150/yr for whole-house), and divides by the gallons produced in a year at your stated daily rate.
The bottled-water comparison uses a flat $1.50 per gallon assumption — this calculator's own baseline, not a sourced national bottled-water price — so treat it as a rough contrast rather than a market figure. What it does show reliably is the shape of the tradeoff: RO's cost per gallon falls as usage rises, because the fixed installed cost is spread across more gallons, while bottled water's per-gallon cost stays flat no matter how much you use.
Why labor still moves the price on a small plumbing job
Even a modest under-sink install is licensed plumbing work in most jurisdictions once it ties into a home's water supply and drain line. The Bureau of Labor Statistics puts plumbers' mean hourly wage at $34.70 nationally — the highest-paid trade among the systems calculators on this site — which is the real force behind this calculator's location multiplier, even on jobs where the unit itself costs less than a day of labor.
Whether reverse osmosis is the right answer
Reverse osmosis is a capable treatment method, and it is also frequently sold to solve problems it does not solve. The starting point is a water test rather than a system quote.
Test first, because the results determine the technology. Hardness is a softener problem, not an RO problem. Sediment wants filtration. Bacteriological contamination wants disinfection. RO addresses dissolved solids, and buying it for the wrong contaminant means paying for a system that leaves the actual issue in place.
There are real trade-offs to weigh even when RO is right. It produces wastewater alongside treated water, it needs cartridge and membrane replacement on a schedule, and it removes dissolved minerals indiscriminately, which changes how the water tastes to some people.
The under-sink versus whole-house decision usually turns on the same test result. If the concern is drinking water, treating one tap is far cheaper. Whole-house treatment is for problems that affect bathing, laundry and appliances — a different and larger scope.
Methodology
Unit, labor, water-surcharge and filter-cost bands are the literal constants in this calculator's module (src/lib/calculators/ro-installation.ts). The whole-house and under-sink ranges above are computed at render by running that module at the inputs named in the text; the whole-house range is read from the dataset (src/data/costs/ro-installation.ts, Angi, retrieved 2026-07-13) rather than typed. Wage figures are BLS OEWS May 2025. No figure is estimated or interpolated.
Sources
- U.S. Bureau of Labor Statistics — OEWS Profile, Plumbers, Pipefitters and Steamfitters (47-2152), May 2025 — accessed 2026-09-07
- Angi — Reverse Osmosis Water Filter Cost (2026) — accessed 2026-07-13
What's included — and what's extra
Usually included
- RO unit & filter stages
- Faucet & tank
- Connection to cold supply & drain
- Basic under-sink install & testing
Often extra
- New drain saddle or air gap
- Electrical outlet for whole-house/permeate pump
- Fridge/ice-maker line
- Remineralization or UV stage
Methodology & sources
The cost figures on this page are generated from a single, sourced cost-data file (Installed by system type. National average estimate for 2026 (~$2,200 average).). Under-sink units are the most common; whole-house RO is a much larger job and may need a drain line and electrical outlet. Labor is $150–$500. Last verified July 2026.
- HomeGuide — Reverse Osmosis System Cost (2026) — retrieved 2026-07-13
- Angi — Reverse Osmosis Water Filter Cost (2026) — retrieved 2026-07-13
About this calculator
How much does reverse osmosis installation cost?
Reverse osmosis installation cost depends on system type. A standard under-sink RO system runs $300–$950 installed, including the unit and professional installation. Multi-stage or premium under-sink systems cost $500–$1,500. Whole-house RO systems cost $4,800–$8,000 installed. Annual filter costs run $40–$150 per year. Compared to bottled water at $0.15–$2.00 per gallon, under-sink RO produces water for $0.01–$0.03 per gallon, paying back in 1–3 years for most households.
What does reverse osmosis remove from water?
RO systems remove 95–99% of dissolved solids including: lead, arsenic, fluoride, nitrates, chromium, chlorine and chloramine, PFAS (forever chemicals), and most other contaminants. RO membranes filter down to 0.0001 microns. What RO does not remove: some pesticides and pharmaceuticals require additional carbon filtration. RO also removes minerals like calcium and magnesium — many quality systems add minerals back.
How often do RO filters need to be replaced?
Pre-filters (sediment and carbon) need replacement every 6–12 months. The RO membrane needs replacement every 2–3 years. Post-filters (polishing carbon) need replacement every 12 months. Total annual filter costs: $40–$80 for under-sink systems, $60–$150 for whole-house. Water quality affects frequency — harder water or high sediment reduces filter life.
Under-sink vs. whole-house RO: which do I need?
Under-sink RO is the right choice for most households — it provides excellent quality drinking and cooking water at low cost. Whole-house RO is only necessary when the entire water supply needs filtration (severe contamination, industrial areas, certain agricultural regions). Whole-house RO wastes 3–4 gallons for every gallon filtered and requires expensive equipment — it's rarely needed for typical residential use.