a water softener can transfer TRACE amount of salt to the water. it is very miniscule amount, that will affect no fish or plants. what is to be considered though is a water softener does remove minerals from the water which can be desireable. if it truly concerns you, pretty much all water softeners have a bypass on the head. push the bypass valve over, run a few gallons of water out the faucet, and you now have unsoftened water. remember to put the valve back so that your house doesnt get the hard water crusty's.