The same numbers, twice
| Source | Range | Average | Updated |
|---|---|---|---|
| This Old House | $150 to $4,800 | $2,475 | March 30, 2026 |
| Bob Vila | $150 to $4,800 | $2,200 | February 29, 2024 |
Identical range. Identical sub-ranges underneath it, as the next section shows. Two years and one month apart.
Bob Vila says where it got the figures: HomeAdvisor. This Old House does not name a source for its range.
Our reading, marked as ours. We found the same pattern on our water softener page, where two publishers printed an identical $200 to $6,000 and one of them stated in a footnote that the data came from Angi. It appears to be the normal condition of this subject rather than a coincidence: a small number of lead-generation platforms produce the cost data, and the guides you find reprint it. What each publisher contributes is the average it computes on top, and here those differ by $275, which is the honest size of the disagreement between them.
So treat the range as one source, not two. It is still useful. It is just not corroborated.
The split that actually decides the price
Both publishers divide the category the same way, and this is the part worth your attention:
| Where the system sits | Cost |
|---|---|
| Point of use, filtering a single faucet | $150 to $1,300 |
| Point of entry, filtering the whole house | $1,000 to $4,800 or more |
Our reading, marked as ours. The gap between those two rows is most of the range. A point-of-use unit under the kitchen sink and a point-of-entry system for the whole house are not cheap and expensive versions of the same purchase; they are different projects with different plumbing. Anyone quoting you "a reverse osmosis system" without saying which one is quoting a word, not a job. Decide the row first and the published range stops being $150 to $4,800 and becomes something you can hold a quote against.
Bob Vila adds two figures at the edges. A whole-house system may need a water softener alongside it for very hard water, which can take the total to $10,000. And commercial systems run $4,000 to $25,000 to purchase, with installation adding $500 to $2,000, which is a useful reminder that a quote in that territory is probably not for a house.
What it does that a cheaper filter does not
This Old House quotes an expert on the distinction:
Reverse osmosis will do everything that a carbon-based [water filtration] system will do. But in addition, it will remove dissolved solids in the water.
Our reading, marked as ours. That single sentence is the whole buying decision. If your complaint is taste, smell or chlorine, a carbon filter addresses it for a fraction of the money. Reverse osmosis earns its price when the problem is dissolved solids, which a carbon filter will not touch. Pay for the membrane when you have a reason to, and the reason comes from a water test rather than from a brochure. Our do I need a water softener page covers how to get that test for about ten dollars.
Note also what reverse osmosis is not: it is not a water softener. It removes minerals rather than exchanging them, and it is normally fitted at one tap rather than treating everything flowing into the house. This Old House's own softener guide nevertheless prices reverse osmosis inside its softener cost table, at a top figure that exceeds the headline range printed at the top of that same page. We show that contradiction with its numbers on our water softener page, where the guide it comes from is in the source list.
The cost that does not stop
Both publishers are clear that the purchase is not the end of it. This Old House: filters are replaced every six months to two years depending on the system, and the membrane every three to five years.
Our note, marked as ours. That is the figure to put next to a quote, because it is the one a salesperson has no reason to mention. A system whose membrane runs to a few hundred dollars every four years changes the comparison against a carbon filter you replace yourself. Ask for the replacement part numbers and their prices before you sign, not after.
One thing about the page itself
This Old House's reverse osmosis guide carries a quote form that submits your details to All Star Pros, a contractor lead service. We mention it for the same reason we mention it elsewhere on this site: the page is useful and we have used it, and it also earns money by passing your details to the people who would do the work. Both things are true at once, and you should know the second one while reading the first.
What to take from this
- Decide point of use or point of entry first. That choice is worth thousands; the brand is worth hundreds.
- The published range comes from one place. Two guides printing $150 to $4,800 is not two opinions.
- Reverse osmosis is for dissolved solids. For taste and chlorine alone, a carbon filter does the job for less, which our softener versus filter page works through.
- Budget the membrane, every three to five years, before you compare systems.
- It is not a softener, and a guide that prices it inside a softener table is mixing two categories.
Sources
- This Old House, How Much Does a Reverse Osmosis System Cost in 2026?, updated March 30, 2026 (the $2,475 average and $150 to $4,800 range, the point-of-use and point-of-entry split, the filter and membrane replacement intervals, the comparison with carbon filtration from its expert, and the lead-capture disclosure on the same page)
- Bob Vila, How Much Does a Whole-House Reverse Osmosis System Cost to Install?, updated February 29, 2024 (the $2,200 average and the $150 to $4,800 range attributed on the page to HomeAdvisor, the same point-of-use and point-of-entry figures, the softener add-on reaching $10,000, and the commercial system range)
Price figures are national US ranges from the sources above as of the date shown. Your local price depends on labor rates, permits and site conditions. Read how we get our numbers.