Absolutely not.. Diferent ph levels and salts in water can make it more or less conductive according to levels.. What is stopping the water board putting conductive pipe joint underground and then this becoming extraneous conductive.. Small copper pipe after stop tap earth to MET no PD between earths in installation, tick jobs a good one!
You are effectively making whatever it is that you have bonded a part of the electrical installation. For example, a metal sink - this cannot introduce a potential (even earth potential), and so is not extraneous and should not be bonded. You would not be making things safer by bonding it.
What would you be giving it a PD too, as everything that introduces a earth path must be bonded!!