Reverse osmosis drinking water systems
RO gives you a dedicated tap for drinking and cooking. Here's what it does well and what to know before you buy.
A reverse osmosis system pushes water through a very fine membrane, along with pre-filters and a final filter, and stores the treated water in a small tank that feeds a faucet at the sink. It reduces dissolved solids, including sodium and many other substances. It usually goes under the kitchen sink, sometimes with a line to the refrigerator.
Why pair RO with a softener?
Salt-based softeners add sodium as they take out hardness, about 8 mg/L for each grain removed according to NDSU Extension, which advises keeping an unsoftened tap for drinking and cooking. An RO faucet does that job while the rest of the house stays soft. Softened water feeding the RO also keeps hardness from scaling the membrane.
What about arsenic?
Arsenic occurs naturally in groundwater across southern New Mexico. Las Cruces Utilities' 2021 report shows it well under the federal limit of 10 parts per billion, and the New Mexico Environment Department recommends that private well owners test for it every year. If a test shows arsenic you want to lower, ask the company which point-of-use systems are independently certified to reduce it, and get a follow-up test after installation.
What about the wastewater?
Home RO units send part of the water they process down the drain, which is why RO is sized for drinking and cooking rather than the whole house. Ask how much water the system you're considering rejects and how the drain line will be connected. If you're on a septic system, ask about that too.
What upkeep does it need?
- Pre-filters and post-filters changed on a schedule
- The membrane replaced less often
- A check of the storage tank pressure
Ask the company what the replacement schedule looks like for your water.
The water treatment company prices the job once it knows your water, your plumbing and what equipment fits. We don't quote prices, and any number you hear over the phone before someone has tested the water and seen the install spot is only a rough starting point.
Where we connect you with help
Common questions
Is reverse osmosis the same as a softener?
No. A softener treats all the water in the house for hardness. RO is a drinking-water filter for one or two taps.
Does RO work on well water?
Often, but test the well first. Hardness, iron and sediment may need treatment ahead of the RO so the membrane isn't fouled.
Related services
More background: Las Cruces hard water guide.
Crusty faucets, cloudy glasses or a softener that gave up?
Call the number above and a local water treatment company will help you sort out what your water needs.