Wear lab gloves and eye protection.
Follow the safety instructions when deal with current.
Always follow general safety
recommendations. Please note that conducting chemistry
experiments you must comply with the relevant legal procedures in
Water decomposes to hydrogen and oxygen under an electric current. Hydrogen gas is produced on the cathode, oxygen gas is produced on the anode. Following the stoichiometry of this reaction, the amount of hydrogen is twice more than amount of oxygen. This is demonstrated by comparing the volumes of produced gases - the volume of hydrogen is twice more than the volume of oxygen.
To increase the conductivity of water, you may add a salt formed from active metal cations and an oxyacid anion (anions).