A kitchen remodel is one of the most common reasons a St. Louis homeowner ends up working around an under-sink reverse osmosis system. Countertops get measured, cabinets come out, and the crew needs the space clear. A few planned steps before the first cabinet moves can prevent leaks, a damaged cabinet floor, or a faucet that never seats correctly again.

Decide What the Remodel Will Disturb

Before anyone touches the system, find out exactly what the remodel affects. Ask your contractor whether the sink is being replaced, whether the faucet is changing, whether the cabinet is coming out, and whether the floor under the sink is being replaced. Each answer changes the plan. If only the countertop is being replaced, the unit may be able to stay in place with the feed closed and the tank valve shut. If the base cabinet is coming out, the whole system needs to be disconnected and moved out of the way.

Shut Off the Feed Water First

Find the valve that feeds the RO system. It is usually a small valve on the cold water line under the sink, sometimes with a separate shutoff on the feed tubing. Close it fully. Then open the RO faucet and confirm that flow slows and stops as the storage tank empties. Closing the main house shutoff works, but it affects every fixture in the home and can make the job harder for the crew, so use it only if the local valve cannot be closed.

Drain the Storage Tank

With the feed closed, leave the RO faucet open and let the storage tank empty. The tank holds pressurized treated water, so it will keep pushing water for a while after the feed is off. Keep towels and a bucket nearby. Once the flow becomes a trickle, close the faucet, then close the small valve on the tank line. This keeps water from moving back toward the work area while you disconnect lines.

Disconnect the Lines in a Sensible Order

Disconnect the lines in an order that keeps spills small. Start with the feed tubing at the valve, then the drain connection, then the tank line, then the faucet line. Put painter's tape on each tube with a note about where it goes before you pull it. Plastic tubing can keep the bend it had in place, so do not cut or reshape tubing unless you are replacing it. If a fitting is stuck, have the crew or a plumber handle it rather than forcing it, since a cracked fitting turns a simple remodel into a water damage repair.

Protect the Parts

  • Cap open tubing ends with clean caps or tape to keep debris out.
  • Store filter housings upright and away from the work area.
  • Keep the storage tank and membrane housing out of dust and out of the path of tools.
  • Keep replacement cartridges sealed in their packaging until they are needed.

Plan the Drain Connection Early

The drain connection is the part homeowners most often forget. If the remodel changes the sink drain, the RO drain saddle or tee may also need to move. Confirm where the RO drain will end up before the new plumbing goes in. A drain that ends in the wrong place, sits too low, or is not secured can move during use and leak into the cabinet. Ask the plumber to check the drain height and make sure the line is not kinked.

Restore the System Slowly

When the remodel is finished, reconnect the lines in reverse order and check each fitting by hand before opening the feed. Open the feed valve slowly and watch every connection for drips. Let the tank refill, then open the RO faucet and run it until the flow looks normal. Some air or sputtering at first is common after a shutdown. Check the faucet, tank line, and drain connection again after the system has run for a while, and once more the next day. Tighten nuts only as much as needed, since overtightening plastic fittings can crack them.

Questions to Settle Before the Crew Starts

  • Who is responsible for disconnecting and reconnecting the RO system?
  • Where will the shutoff valves be after the remodel?
  • Will the drain connection stay in the same place?
  • Is the faucet being replaced or only reinstalled?
  • Who checks for leaks once the system is back online?

Permits and Inspections

If your St. Louis remodel includes plumbing changes that need a permit, ask your contractor which inspections apply and whether the RO drain and supply lines are part of the review. Getting the answer in writing before work starts makes it easier to decide who checks the system after the job is done.