Reverse Osmosis Systems

For one kitchen tap, a countertop or a whole business. Pre-filters, a membrane and a post-filter in every system.

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56 Products

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Answer four quick questions and we'll narrow this collection down to your best three.

Where will the system go?

Ordering from Rein Water

What to expect

  • Ships direct from the manufacturer

    Every order is packed and shipped by the brand that makes it. We submit your order to them within 2 business days.

  • Estimated delivery on product pages

    Brondell, Crystal Quest and Waterdrop product pages show a dated delivery window under the buy button before you order.

  • Returns by brand

    Each manufacturer sets its own return window and restocking fee. Check the terms for your brand before you order.

    Return terms by brand

  • Tracking as soon as it ships

    We email your tracking number within 1 business day of the shipment leaving the manufacturer.

How to choose a reverse osmosis system

A reverse osmosis (RO) system pushes water through a fine membrane and a series of pre-filters and post-filters, then sends the treated water to its own faucet or dispenser. This collection covers three sizes of job: under-sink systems for one kitchen, countertop systems that connect to a faucet with no plumbing, and commercial systems built for restaurants, offices and production.

Who it is for

Under-sink and countertop RO suits households that want treated water for drinking and cooking. Commercial systems are for businesses that need hundreds to tens of thousands of gallons a day.

What to compare

  • Capacity (GPD): the rated gallons per day. Home systems here run from 50 GPD to 1,600 GPD; commercial systems go up to 24,000 GPD.
  • Stages: the number of filters in the chain, from 3 to 17 in this collection. More stages usually means more pre-treatment and post-treatment, not a finer membrane.
  • Tank or tankless: tank systems store treated water and fit smaller budgets; tankless systems deliver on demand and save cabinet space.
  • Install type: countertop units connect to a faucet with no tools, under-sink units need a drain connection and a faucet hole, and commercial systems are installed by a plumber.

Larger systems ship by freight. Request a quote from the product page and we confirm the delivered cost before you commit.

Common questions

Most under-sink systems are designed for DIY installation with a drain saddle and a dedicated faucet. If your countertop needs a new hole drilled, or you would rather not work under the sink, a local plumber can fit one. Our installer finder shows local plumbers and installers by ZIP code.

A tank system fills a small pressurized tank so water is ready when you open the tap. A tankless system filters on demand at a higher flow rate and takes up less cabinet space. Both types are in this collection.

Commercial and light-commercial systems are quoted. Request a quote from the product page with your delivery address and daily water need, and we reply with the system price and freight together.

PFAS reduction is claimed model by model. Several systems here list PFAS among the contaminants they reduce, and several are certified to NSF/ANSI 58. Check the reduction list and the certifications on each product page for the exact claim before you buy.

Systems in this collection currently range from about $140 to about $2,900 before shipping; commercial-grade RO units from WaterWorld USA are sold by quote. Price follows daily output, stages and tank or tankless design.