If you see milk drops above the valve during assembly, or any leakage around the connection of the neck and bottle during pumping, check these things:

  • Are your bottles filled above the 5oz / 150ml marking? If yes, it's possible that it will back up and exit out of the valve top. If you pump more than 5oz per side, make sure to switch out bottles before they completely fill up.
  • Is there milk in the "nipple tunnel" after pumping? If yes, make sure milk has completely drained from the flange before turning OFF the pump. To do this, if you see milk pooling up in the end of the nipple tunnel, lean back for a couple pump cycles to allow all that milk to completely fall into the bottle before turning OFF the pump and removing your Flow.