If your iSpring water tastes exactly like your tap water, the reverse osmosis membrane is not filtering. Either it is not installed or water is bypassing it.
- First, verify the blue RO membrane is inside the stage 4 housing. It comes sealed in plastic; if you never put it in, that is the issue.
- Check all tubing connections, especially around the membrane housing and the final stages. An incorrect hookup can let untreated water through.
- Test the TDS of your tap water and the RO water. You should see a reduction of at least 90%. If the numbers are nearly identical, the membrane is not working.
- If you get some reduction but not 90% or more, the automatic shut-off valve could be faulty or the membrane itself is defective.
If the membrane is missing, install it. If connections are wrong, redo them. If the system is plumbed correctly but performance is poor, contact iSpring support—you likely need a replacement part.