The cost of a reverse osmosis system, itemized piece by piece

Advertised prices, verified

How to price out a reverse osmosis purchase

1. Pick the format before you compare anything. A countertop unit sits on the counter and needs no plumbing, an under-sink system feeds one dedicated faucet, and a whole-house RO treats every tap. Comparing prices across formats tells you nothing, so decide which problem you are solving first.
2. Compare published unit prices in the table. Use the vendor prices in the table below as your baseline. They come from the vendors' own product pages, so they reflect what you would actually pay at checkout before any installer or retailer markup gets added on top.
3. Add installation if the system needs plumbing. Under-sink systems need a tee into the cold line, a hole for the dedicated faucet, and a drain saddle for the reject line. Handy owners do this in an afternoon; everyone else should get a plumber's quote and add it to the unit price.
4. Budget the recurring cartridge cost. Prefilters and postfilters change roughly yearly and the membrane lasts several years, sooner on hard or heavily loaded water. Price a full replacement set before you buy, because a cheap unit with expensive cartridges costs more within a few years.

What moves the price up or down

Stage count is the most visible driver: a basic system pairs a sediment prefilter, a carbon block, and the membrane, while higher-stage systems add remineralization, UV, or extra polishing carbon. Each stage adds to the sticker price and, more importantly, adds a cartridge you will keep buying.

Tankless under-sink systems cost more up front than tank systems but free up cabinet space and avoid storage-tank maintenance. Whole-house RO is a different purchase altogether: it needs a large membrane, a storage tank, a repressurization pump, and usually pretreatment, which is why it sits far above point-of-use pricing in the table.

The ongoing cost nobody quotes up front

Reverse osmosis also sends reject water to the drain, and the membrane only lasts if the prefilters ahead of it are changed on schedule. If your supply is hard, a softener ahead of the RO protects the membrane and stretches its life, which is a real cost consideration for well owners: our well water testing guide explains how to find out what your membrane will actually be facing.

Common questions

Does the median price in the table include installation?

No. The table shows what vendors publish for the equipment itself, so the $1,531 figure is the system price; plumbing work for an under-sink or whole-house install is quoted separately by your installer.

Is a whole-house reverse osmosis system worth it over under-sink?

Only when a contaminant needs removing at every tap, not just for drinking. Most households solve taste and drinking-water concerns with an under-sink unit and treat whole-house problems like hardness or iron with dedicated equipment instead.

How long does a reverse osmosis system last?

The housings, faucet, and tank commonly serve a decade or more when the cartridges are changed on schedule. The membrane itself is a consumable that gets replaced every few years, sooner if prefilters are neglected.

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