Reverse osmosis drinking water
A separate tap for drinking and cooking water, filtered at the kitchen sink.
A reverse osmosis system pushes water through a fine membrane and a set of filters to produce drinking and cooking water at one faucet, usually the kitchen sink. In the Rochester area it's most often added alongside a softener, or on a private well where a test turned up something the household wants out of its drinking water.
Why people add RO here
- Softened water. RPU recommends keeping a separate, unsoftened supply for cooking and drinking if you use a softener. An RO tap is one way to do that.
- Private wells. Nitrate is a concern in southeastern Minnesota's karst landscape. Olmsted County has published videos on nitrate testing and on maintaining RO systems.
- Taste. Some people simply prefer the taste of RO water for coffee, ice and cooking.
What to know before you buy
RO is a point-of-use system, sized for drinking and cooking, not the whole house. It sends some water to the drain as it works. Filters and the membrane need replacing on a schedule, and the system should be sanitized periodically; Olmsted County's video shows how. If you're treating a well for nitrate, ask the company for the system's performance data for nitrate and retest the treated water after installation.
What affects the cost
The number of filter stages, tank size, faucet style, whether a line runs to the refrigerator, and the cost of replacement filters over time. Ask about yearly upkeep as well as the install price.
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Common questions
Does RO remove nitrate?
RO can reduce nitrate in drinking water when the system is designed for it. Test the treated water after installation to confirm.
How often do RO filters need changing?
It depends on the system and your water. Pre-filters are typically changed more often than the membrane. Ask the company for a schedule.
Related services
More background: Olmsted County hard water guide.
Crusty faucets or a softener that quit?
One call puts you in touch with a water treatment company that works in Rochester and nearby towns.