Summer storms and winter ice are part of life in St. Louis, and a power outage can leave a reverse osmosis system in an odd state. Many under-sink units run on tank pressure alone, but some homes also have an electric booster pump, a powered feed valve, or a faucet with a light. Knowing what needs electricity, and what to check when the power returns, can save a service call and help the system keep working as it should.
Find out what needs power before the storm
Spend a few minutes under the sink and behind the cabinet. Look for a plug, a pump, or a small transformer, and note where each cord runs. Make sure you can reach the outlet with a flashlight. Keep a flashlight in the kitchen, and know where your home water shutoff valve is, since you may need it if a line fails during or after the event.
What to do during the outage
- Leave the electric pump off or unplugged so it does not restart suddenly when power comes back.
- Use the faucet only as needed. The storage tank still holds water, but repeated draws while the system is off can leave it low.
- Keep the cabinet door open if you need light, and move food and cleaning supplies away from the unit so nothing gets knocked over in the dark.
- Avoid trying repairs by flashlight. Wait for daylight or steady lighting before you open fittings.
Checks once the power returns
Give the house a short time to settle before you test anything. Power can flicker as utility service is restored, and waiting lets the rest of the home stabilize. Then work through these checks in order.
- Plug the pump back in or switch it on, and listen for a steady hum. Rapid clicking or a pump that will not start is a reason to switch it off and stop.
- Look under the sink for drips at each fitting, the filter housings, and the drain line. Dry the area with a towel and check again after a few minutes.
- Run the faucet briefly and watch the flow. A slow stream after an outage can point to a stalled pump, or to a filter that was already close to needing a change.
- If your unit has an indicator light or display, check whether it reset to a default screen or showed an error code. Write down what you see.
- Run water for a short time and notice any change in taste or smell compared with what you usually get.
Cold snaps and frozen lines
Ice storms in and around St. Louis can freeze supply tubing in cabinets along exterior walls. If the cabinet stayed cold for a long stretch, look over the tubing before you open the supply. Check for cracks, bulges, brittle spots, and any kinks near fittings. A line that froze can split as it thaws, so do not assume it is fine just because the water runs.
If you see damage, close the cold water feed valve to the unit, leave the faucet open to release pressure, and call a licensed plumber. Do not try to force a frozen fitting or bend a line back into shape.
Keep a simple record
Write down the date and time the power went out, when it came back, and anything you noticed afterward. If the outage lasted long enough to cause a problem, a short note helps whoever looks at the system later, whether that is you, a plumber, or a repair technician. Include whether the pump needed a reset and whether the faucet flow changed over the next day or two.
When to stop and call for help
Turn off the pump and close the feed valve if you see active water leaking, smell something burnt near the electrical parts, or notice a pump that keeps starting and stopping. Those are signs to get professional help rather than keep testing. For routine questions after a storm, start with the checks above, and keep your notes handy for the conversation.