The reason why I did not use the expression "interior pipe" was that any connection made to or disconnecting of (ie use of plastic pipe) buried utility water pipe would not leave bathtub, etc electrically hot. I saw no need to specify 'interior' pipes since bottom line concept is to not dump 'safety ground' electricity into pipes. But HorneTD makes a good point. Others may not have understood what I assumed to be obvious.
To summarize for the benefit of others, it is bad practice (even if it is legal in Canada) to safety ground a wall receptacle to household water pipes. Electrical connections to pipes are to remove electricity from those pipes. Connection to dump electricity into pipes (water, gas or sewer) is not desirable.
In the OPs case, putting those receptacles on a GFCI is strongly recommended (as one of two possible solutions). The acceptable connection is wire dedicated for that safety function; connected to circuit box safety ground. Even if it is no longer acceptable by code (and I believe was a code change), a separate 12 AWG green colored ground wire is safer than connecting to household pipes. Dedicated earthing of wall receptacle (ie throw a wire out the window to a ground rod) accomplishes little for human safety and would be a code violation. That ground rod outside the window was simply a bad idea based in confusion between safety ground verses earth ground.
HorneTD lists code approved methods of safety ground> If you would only add the word interior before water pipe when making