How much does a whole house reverse osmosis system cost to buy and run

Advertised prices, verified

What you are paying for, piece by piece

1. The membrane assembly. Whole house units use larger membranes than an under sink system and often several in parallel to produce enough water for a household. This is the core hardware cost and the element that is eventually replaced on a schedule set by your feed water quality.
2. Storage and repressurization. Membranes produce water slowly, so treated water fills an atmospheric storage tank and a separate pump pushes it back into the house at usable pressure. That tank and pump are a large share of the installed cost and take up real floor space.
3. Pretreatment that is not optional. Sediment filtration, carbon to remove chlorine that would destroy the membrane, and softening or antiscalant to stop hardness scaling it are all required upstream. Skipping any of them shortens membrane life dramatically and is the fastest way to a large repair bill.
4. Drain capacity and water use. Reverse osmosis rejects a portion of the feed water to drain to carry away the contaminants it removes. The house needs a drain that can take it continuously, and your water bill or well pump run time rises accordingly for as long as the system runs.
5. Remineralization, if you want it. Water leaving a membrane is very low in dissolved minerals, which tastes flat and can be aggressive toward some plumbing materials. A calcite or blended remineralizing stage after the tank addresses both, and is a standard part of a well specified whole house build.

Whether your house needs it at all

Whole house reverse osmosis is justified in a small number of situations: brackish or very high dissolved solids water, a contaminant present at levels that carbon and specialty media cannot handle, or a supply where the same contaminant needs treating at every fixture rather than only at the drinking tap. Outside those cases it is the wrong tool.

For most households the same protection at the point that matters costs a fraction of the price. A small under sink unit treats drinking and cooking water, while whole house nuisances such as chlorine, sediment, iron and hardness are handled by conventional media on the main line. Ask a supplier quoting from the table below to explain, from your test result, why that split will not work for you.

The ongoing cost most quotes leave out

Running cost has three parts: prefilters and carbon changed on schedule, membranes replaced periodically, and the pump running whenever the house draws water. Add the rejected water going to drain, which continues for the life of the system, and the ten year picture is very different from the install price alone.

Ask any installer for the expected membrane life on your specific water and the replacement cost of the membrane set, in writing. Feed water quality drives that number more than anything else, which is why good pretreatment is the cheapest insurance available on a system of this class.

Common questions

What does whole house reverse osmosis cost?

Local installed prices centre on $1,531, and the table below shows the range. Pretreatment, storage, pumping and drain work are frequently priced separately.

Why is it so much more than an under sink system?

Because it has to produce and store enough water for an entire household and repressurize it, rather than filling a small tank for one faucet.

Does it waste water?

Yes, by design. A share of the feed water is sent to drain carrying away what the membrane removed, which raises your water use for as long as the system operates.

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