Reverse Osmosis Tanks Can Be Sanitized Without Special Tools

Sanitizing the storage tank of small, undersink reverse osmosis units doesn’t have to be a high tech procedure.  It is simply a matter of getting some common household bleach into the tank and giving it a little time to work. To do this procedure, you’ll need some standard household bleach and an eyedropper.

1. Turn off the inlet water to the RO unit, lock the ledge faucet open,  and allow all the water to run from the storage tank.

2. When no water is coming from the faucet, turn off the valve at the top of the storage tank and remove the tube from the tee that connects the tank to the RO unit.  (Not from the tank end, but the other end of the tube.)

3. Shake as much water as you can from the tube and use an eyedropper to drop as much bleach as you can into the empty tube.  A few drops is plenty.  Careful–bleach can be messy and it can discolor items that it falls on.

4. Reconnect the tube to the tee, being careful not to allow the bleach to run from the tube.

5. Close the ledge faucet, open the tank valve, and turn on the inlet water to the RO unit. Allow the RO unit to fill the tank. This will take at least a couple of hours. As the tank fills, the bleach is swept into the tank.

6. Do not use the water for at least 3 hours after the tank is full.  Letting it sit overnight is best.

7. After you have given the bleach sufficient time to work, start using the unit.  You do not need to drain the tank.  The unit’s post filter will remove the bleach from the water.

Note that this procedure sanitizes the storage tank only.  Sanitizing other parts of the unit is a more complicated issue.